Fe-doped g-C3N4 with duel active sites for ultrafast degradation of organic pollutants via visible-light-driven photo-Fenton reaction: Insight into the performance, kinetics, and mechanism

The photo-Fenton process provides a sustainable and cost-effective strategy for removing refractory organic contaminants in wastewater. Herein, a high-efficient Fe-doped g-C3N4 photocatalyst (Fe@CN10) with a unique 3D porous mesh structure was prepared by one-pot thermal polymerization for ultrafast degradation of azo dyes, antibiotics, and phenolic acids in heterogeneous photo-Fenton systems under visible light irradiation. Fe@CN10 exhibited a synergy between adsorption-degradation processes due to the co-existence of Fe3C and Fe3N active sites. Specifically, Fe3C acted as an adsorption site for pollutant and H2O2 molecules, while Fe3N acted as a photocatalytic active site for the high-efficient degradation of MO. Resultingly, Fe@CN10 showed a photocatalytic degradation rate of MO up to 140.32 mg/L min-1. The dominant ROS contributed to the removal of MO in the photo-Fenton pathway was hydroxyl radical (•OH). Surprisingly, as the key reactive species, singlet oxygen (1O2) generated from superoxide radical (•O2-) also efficiently attacked MO in a photo-self-Fenton pathway. Additionally, sponge/Fe@CN10 was prepared and filled in the continuous flow reactors for nearly 100% degradation of MO over 150 h when treating artificial organic wastewater. This work provided a facile route to prepare highly-active Fe-doped photocatalysts and develop a green photocatalytic system for wastewater treatment in the future.

[Analysis of factors associated with futile recanalization after endovascular treatment for acute ischemic stroke with large vessels occlusion in anterior intracranial circulation]

Objective: To analyze the related factors of futile recanalization (FR) after emergency endovascular treatment of large artery occlusion in anterior circulation. Methods: Three studies on endovascular treatment of acute anterior circulation large vessels occlusion stroke were selected, and their data were merged for retrospective analysis. Patients were divided into the FR group and favorable prognosis group according to the functional prognosis. Risk factor analysis was conducted using multivariate logistic regression. Results: A total of 1 581 patients were finally included, with 858 (48.9%) patients in favorable prognosis group and 926 (51.91%) patients in FR group. Among them, there were 939 males and 642 females, with a mean age of (65±12) years. Multivariate logistic regression analysis showed that National Institute of Health Stroke Scale (NIHSS) score (OR=1.089,95%CI:1.066-1.113), puncture to recanalization time (OR=0.756, 95%CI:0.586-0.971), age (OR=1.04,95%CI:1.029-1.051), serum glucose (OR=1.101,95%CI:1.062-1.143), systolic blood pressure (OR=1.005,95%CI:1.001-1.010), passes≥3(OR=1.941,95%CI:1.294-2.941)Alberta stroke program early CT (ASPECT) score (OR=0.919,95%CI:0.847-0.996), occlusion site (M1 segment of middle cerebral artery, OR=0.744,95%CI:0.565-0.980) and collateral circulation [(2 points, OR=0.757, 95%CI:0.581-0.985); (3-4 points, adjusted OR=0.640, 95%CI: 0.472-0.866)] were independent factors of FR. Conclusion: The incidence of FR in patients with large artery occlusion in anterior circulation who achieve satisfied reperfusion after endovascular treatment is high. Higher NIHSS score, longer puncture to recanalization time, older age, higher serum glucose and systolic blood pressure are risk factors, while lower ASPECTS, occlusion in cerebral middle M1 segment, better collateral circulation are protective factors.

[Pay attention to the futile recanalization management of patients with acute ischemic stroke]

Vascular recanalization therapy has been proven to be one of the most effective treatments for acute ischemic stroke (AIS) worldwide. Recently, the neurological functions have dramatically improved for AIS patients receiving endovascular thrombectomy, especially after the issue and promotion of evidence from different clinical studies. But nearly 50% of the patients had unfavorable clinical outcome even after successful recanalization [modified thrombolysis in cerebral infarction (mTICI)≥2b/3], which was termed as"futile recanalization". The mechanisms are complex, which may be related to poor collateral circulation, microthrombus and small artery reocclusion. The most significant pathophysiological change is brain tissue hypoperfusion although complete opening of the large artery, known as"no-reflow phenomenon". Therefore, it is urgent to manage the complications after vascular recanalization, such as hemorrhagic transformation, hyperperfusion syndrome, vascular re-occlusion, and even surgery-related complications (arterial dissection, contrast-induced encephalopathy), and future research is warranted to focus on the strategy of drugs with multi-target protection combined with vascular recanalization treatment. The current article covers the review, original research and case report focusing on this topic, aiming to raise clinical questions and call for more contribution to explore the mechanism and potential therapeutic strategy of futile recanalization, and thus provides more selections on the improvement of clinical outcome for AIS patients.

[Construction and quality assurance of metagenomic next-generation sequencing platform in pathogen detection]

Early diagnosis remains the key to prevent and control infectious diseases. In recent years, metagenomic next-generation sequencing (mNGS) technology breaks through the limitations of conventional culture methods or targeted molecular detection methods. It improves the diagnosis and treatment level of difficult and rare infectious pathogens through the shotgun high-throughput sequencing to conduct unbiased and rapid detection of microorganisms in clinical samples, which has been widely recognized in clinical practice. Due to the complex detection process of mNGS, there are no uniform specifications and requirements at present. Meanwhile, most laboratories lack of relevant talents at the initial stage of platform establishment, which poses severe challenges to the construction and quality control of the mNGS platform. Based on the practical experience in the construction and operation of the mNGS laboratory of Peking Union Medical College Hospital, the current article summarizes the hardware requirements for the establishment of the mNGS laboratory, the establishment and evaluation methods of the mNGS testing system and the quality assurance after the clinical application, and comprehensively introduces the suggestions for the standardized construction and operation of the mNGS testing platform and quality management system.

Enhancing extracellular electron transfer through selective enrichment of Geobacter with Fe@CN-modified carbon-based anode in microbial fuel cells

Microbial fuel cells (MFCs) have been demonstrated as a renewable energy strategy to efficiently recover chemical energy stored in wastewater into clean electricity, yet the limited power density limits their practical application. Here, Fe-doped carbon and nitrogen (Fe@CN) nanoparticles were synthesized by a direct pyrolysis process, which was further decorated to fabricate Fe@CN carbon paper anode. The modified Fe@CN anode with a higher electrochemically active surface area was not only benefit for the adhesion of electrochemically active microorganisms (EAMs) and extracellular electron transfer (EET) between the anode and EAMs but also selectively enriched Geobacter, a typical EAMs species. Accordingly, the MFCs with Fe@CN anode successfully achieved a highest voltage output of 792.76 mV and a prolonged stable voltage output of 300 h based on the mixed culture feeding with acetate. Most importantly, the electroactive biofilms on Fe@CN anode achieved more content ratio of proteins to polysaccharides (1.40) in extracellular polymeric substances for the balance between EET and cell protection under a harsh environment. This work demonstrated the feasibility of development on anode catalysts for the elaboration of the catalytic principle about interface modification, which may contribute to the practical application of MFC in energy generation and wastewater treatment.

Visible imaging system with changeable field of view on the HL-2A tokamak

A new visible imaging system characterizing a flexible optical design and delivering high resolution frames is established on the HL-2A tokamak. It features a modular configuration, consisting of a front-end imaging lens, a set of bilateral telecentric relay lenses, and a camera. To avoid the effects of plasma radiation (x and gamma-rays) and magnetic field variation on the camera, it should be away from the coils. Therefore, the length of the relay lenses determines the total size of the imaging system. The main feature of this imaging system is to realize the variation of field of view (FOV) by interchanging the front-end prime lenses or by using a zoom lens directly rather than designing the optical system afresh, which lowers the cost drastically. The primary purpose of varying FOV is to enrich the versatility of this system, i.e., focusing on a narrow FOV such as gas puff imaging or a wide FOV such as the plasma cross sections. During the HL-2A experiments, this visible imaging system is used to provide high quality pictures of the plasma-wall interaction, divertor detachment, pellet injections, and so on. The frames confirmed that a strong radiation close to the X point is correlated with the completely detached inner target.

[Research advances on the pathogenesis and diagnosis of pyoderma gangrenosum]

Pyoderma gangrenosum (PG) is a rare neutrophilic dermatosis, closely associated with the immune system. Its pathogenesis is currently not clear. The lack of specificity in the clinical manifestations and histopathological changes of PG leads to a long clinical diagnosis cycle and even misdiagnosis, which is easy to delay treatment or promote the deterioration of ulcer wound. The diagnosis of this disease is still very difficult, which poses a great challenge to wound repair practitioners. This article reviews the research advances on the pathophysiology, clinical features, and diagnosis of PG in recent years, with the aim of providing reference for relevant clinical practitioners.

Quorum sensing signals improve the power performance and chlortetracycline degradation efficiency of mixed-culture electroactive biofilms

Electroactive biofilms (EABs) play an important role in bioelectrochemical systems due to their abilities to generate electrons and perform extracellular electron transfer (EET). Here, we investigated the effects of quorum sensing (QS) signals on power output, chlortetracycline degradation, and structure of EABs in MFCs treating antibiotic wastewater. The voltage output of MFCs with C4-HSL and PQS increased by 21.57% and 13.73%, respectively, compared with that without QS signals. The chlortetracycline degradation efficiency in closed-circuit MFCs with C4-HSL and PQS increased by 56.53% and 50.04%, respectively, which resulted from the thicker biofilms, higher biomass, and stronger activities. Additionally, QS signals induced the heterogeneous distribution of EPS for a balance between self-protection and EET under environmental pressure. Geobacter prevailed by the addition of QS signals to resist high chlortetracycline concentration. Our results provided a broader understanding on regulating EABs within electrode interface to improve their performance for environmental remediation and clean energy development.

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The voltage output of MFCs was enhanced with the addition of QS signals

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QS signals increased the bioelectrochemical degradation efficiency of CTC

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EABs exhibited heterogeneity in composition and interaction by the QS signals

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QS signals induced a balance between self-protection and EET of EABs

Apigenin Improves Hypertension and Cardiac Hypertrophy Through Modulating NADPH Oxidase-Dependent ROS Generation and Cytokines in Hypothalamic Paraventricular Nucleus

Apigenin, identified as 4', 5, 7-trihydroxyflavone, is a natural flavonoid compound that has many interesting pharmacological activities and nutraceutical potential including anti-inflammatory and antioxidant functions. Chronic, low-grade inflammation and oxidative stress are involved in both the initiation and progression of hypertension and hypertension-induced cardiac hypertrophy. However, whether or not apigenin improves hypertension and cardiac hypertrophy through modulating NADPH oxidase-dependent reactive oxygen species (ROS) generation and inflammation in hypothalamic paraventricular nucleus (PVN) has not been reported. This study aimed to investigate the effects of apigenin on hypertension in spontaneously hypertensive rats (SHRs) and its possible central mechanism of action. SHRs and Wistar-Kyoto (WKY) rats were randomly assigned and treated with bilateral PVN infusion of apigenin or vehicle (artificial cerebrospinal fluid) via osmotic minipumps (20 μg/h) for 4 weeks. The results showed that after PVN infusion of apigenin, the mean arterial pressure (MAP), heart rate, plasma norepinephrine (NE), Beta 1 receptor in kidneys, level of phosphorylation of PKA in the ventricular tissue and cardiac hypertrophy, perivascular fibrosis, heart level of oxidative stress, PVN levels of oxidative stress, interleukin 1β (IL-1β), interleukin 6 (IL-6), iNOS, monocyte chemotactic protein 1 (MCP-1), tyrosine hydroxylase (TH), NOX2 and NOX4 were attenuated and PVN levels of interleukin 10 (IL-10), superoxide dismutase 1 (Cu/Zn-SOD) and the 67-kDa isoform of glutamate decarboxylase (GAD67) were increased. These results revealed that apigenin improves hypertension and cardiac hypertrophy in SHRs which are associated with the down-regulation of NADPH oxidase-dependent ROS generation and inflammation in the PVN.

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.

A remote gain controlled and polarization angle tunable Doppler backward scattering reflectometer

Remote control of the diagnostic systems is the basic requirement for the high performance plasma operation in a fusion device. This work presents the development of the remote control system for the multichannel Doppler backward scattering (DBS) reflectometers. It includes a remote controlled quasi-optical system and a remote intermediate frequency (IF) amplifier gain control system. The quasi-optical system contains a rotational polarizer, its polarization angle is tunable through a remote controlled motor, and it could combine the microwave beams with a wide frequency range into one focused beam. The remote IF gain control system utilizes the digital microcontroller (MCU) technique to regulate the signal amplitude for each signal channel. The gain parameters of amplifiers are adjustable, and the feedback of working status in the IF system will be sent to MCU in real time for safe operation. The gain parameters could be controlled either by the Ethernet remote way or directly through the local control interface on the system. Preliminary experimental results show the effectiveness of the remote controlled multichannel DBS system.

Plasma metabolome alteration in dairy cows with left displaced abomasum before and after surgical correction

Left displaced abomasum (LDA) leads to substantial changes in the metabolism of dairy cows. Surgical correction of LDA can rapidly improve the health of cows; however, changes in metabolism following surgery are rarely described. To investigate the changes of plasma metabolome in cows with LDA before and after surgical correction, blood samples were collected from 10 healthy postpartum cows and 10 cows with LDA on the day of diagnosis, then again from the LDA cows 14 d after surgery. Serum nonesterified fatty acid, β-hydroxybutyric acid, cortisol and histamine concentration, and antioxidant enzyme (superoxide dismutase and glutathione peroxidase) activities were evaluated, and the metabolic profile in plasma was analyzed using ultra-high-performance liquid chromatography time-of-flight mass spectrometry. The results demonstrated that cows with LDA experienced severe negative energy balance and oxidative stress, which can be improved by surgical correction. The metabolic profile was analyzed using multidimensional and univariate statistical analyses, and different metabolites were identified. In total, 102 metabolites differed between cows with LDA and healthy cows. After surgical correction, 65 metabolites changed in cows with LDA, compared with these cows during the LDA event. Following surgical correction, AA levels tended to increase, and lipid levels tended to decrease in cows with LDA. Pathway analysis indicated marked changes in linoleic acid metabolism, Arg biosynthesis, and Gly, Ser, and Thr metabolism in cows at the onset of LDA and following surgical correction. Surgical treatment reversed the changes in AA and lipid metabolism in cows with LDA.

Visible wide-angle view imaging system for the first plasma on the HL-2M tokamak

The wide-angle view imaging system, in terms of a tangential view diagnostic with field of view (FOV) of 56.8° and a downward-looking diagnostic from the top of the machine with FOV of 94.7°, has been newly constructed for the first plasma of the HL-2M tokamak achieved in December 2020. Its mission in this stage is to monitor the plasma evolution during its startup, sustainment, and disruption in the visible spectral range as well as the plasma-wall interaction. For the latter ultrawide view diagnostic, nearly three-quarters of the divertor region and half the area of the inner wall are in the view range. Both the diagnostics are characterized by a similar optical structure, i.e., the light emission from the plasma is collected by a front-end lens and transferred through an imaging fiber bundle to the camera. This optical structure is suitable for application in the complex tokamak environment mainly because the fiber bundle is flexible. Photos of glow discharges are acquired prior to the first plasma for testing the FOVs in the vacuum vessel. The spatial resolution is ∼4mm for the tangential view diagnostic and ∼10mm for the downward-looking diagnostic. The temporal resolutions, ranging from 90 to 360 Hz by changing the region of interest or binning acquisition mode of the color camera, are applied to record the plasma evolutions and/or dust creation events during the first plasma campaign.

[Diagnosis and endoscopic treatment of blunt laryngeal trauma with arytenoid injury]

Objective: To investigate the clinical characteristics, diagnosis, endoscopic surgical procedures, and therapeutic effect of blunt laryngeal trauma with arytenoid injury. Methods: We retrospectively reviewed 12 patients who suffered blunt laryngeal trauma with laryngeal mucosa avulsion and arytenoid region injury at the Department of Otorhinolaryngology Head and Neck Surgery, Beijing Tongren Hospital from April 2007 to December 2018. Among the 12 patients, 10 were males, 2 were females, aged from 7 to 48 years old, with a median age of 21 years old. All patients were performed with transoral endoscopic laryngeal microsurgery under general anesthesia. Clinical characteristics, laryngoscopic signs, laryngeal CT, endoscopic surgical findings and procedures, and therapeutic effect were analyzed. The subjective and objective parameters of the voice quality of patients before and after surgery were compared using SPSS 22.0 statistical software by paired T test. Results: All patients had a history of obvious dysphonia immediately after trauma, accompanied by throat pain and hemoptysis without obvious dyspnea and dysphagia. Slight subcutaneous emphysema was found in 3 patients by physical examination. Laryngoscope revealed that 14 sides of vocal folds immobilized, arytenoid and/or ventricular region and posterior glottis mucosa were avulsed in 4 patients within 48 h of injury, and arytenoid cartilage was exposed in 4 sides. The arytenoid and ventricular regions were covered with thick pseudo-membrane or granulation, with abnormal structure in 8 patients with damage of more than 48 h. Intraoperative exploration revealed that there were 17 sides of arytenoid region (bilateral 5 cases, unilateral 7 cases) with varying degrees of injury. There was only limited laceration on three sides of the vocal folds. The lateral ventricular and vocal fold mucosae were avulsed vertically from the arytenoid region and arytenoid cartilage was exposed in 14 sides, among which 6 sides had abnormal arytenoid cartilage morphology and 8 sides had fracture displacement. Laryngeal CT showed irregular thickening of lateral glottis and/or supratroglottic structures in patients with vocal folds immobility, among which asymmetry of arytenoid cartilage structure on both sides in 3 cases and displacement in 2 cases were found. Restoration and microsuture of the fractured arytenoid, perichondrium and avulsion laryngeal mucosa under the direct laryngoscope were performed. The degree of dysphonia was significantly improved immediately after laryngeal microsurgery, the voice significantly improved in G, R, B, A, jitter, shimmer, NHR, and MPT three months after surgery(t=12.792, 12.792, 10.340, 3.276, 2.865, 3.781, 3.173, 3.090, respectively, P<0.05). Except for 1 patient with scar on vocal fold, all the other patients had normal laryngeal morphology and normal vocal fold movement. No laryngeal stenosis was found during the follow-up period. Conclusions: For patients with blunt laryngeal trauma, the injury of arytenoid region and arytenoid cartilage should be evaluated if there is obvious hoarseness, vocal fold immobility, avulsion of ventricular/vocal folds mucosa, or structural abnormality of arytenoid region under laryngoscopic examination. For highly suspected cases, microrphonosurgery under the direct laryngoscope should be performed as soon as possible, which can effectively reduce the occurrence of vocal fold movement disorders and laryngeal scar/stenosis, reconstruct the normal laryngeal structure, and restore the vocal function.

Fast charge exchange recombination spectroscopy on HuanLiu-2A tokamak

A Fast Charge eXchange Recombination Spectroscopy (CXRS) diagnostic with eight radial channels has been implemented on a HuanLiu-2A (HL-2A) tokamak with a time resolution of up to 10 kHz monitoring helium II spectra or 1 kHz monitoring carbon VI spectra. The crucial aspects of the fast CXRS are to improve the spectral intensity and the acquisition frequency. The spectral intensity has been greatly enhanced by customized fiber bundles. The main boost in optimizing the acquisition frequency is achieved by binning more pixel rows of the charge coupled device (CCD) representing one radial channel and by reducing the effective image area of the CCD. Consequently, the sawtooth oscillations of ion temperature and rotation velocity are continuously observed for the first time in the HL-2A tokamak.

Age-Dependent Changes in the Plasma Proteome of Healthy Adults

OBJECTIVE

Human blood plasma is a complex that communicates with most parts of the body and reflects the changes in the state of an organism. Identifying age-related biomarkers can help predict and monitor age-related physiological decline and diseases and identify new treatments for diseases.

METHODS AND PARTICIPANTS

In this study, TMT-LC-MS/MS was utilized to screen differentially expressed plasma proteins in 118 healthy adults of different ages. Participants were divided into three groups: 21-30 years of age (Young), 41-50 years of age (Middle) and ≥60 years of age (Old).

RESULTS

The number of differentially expressed proteins in the comparisons of Young vs Middle, Middle vs Old and Young vs Old were 82, 22 and 99, respectively. These proteins were involved in numerous physiological processes, such as "negative regulation of smooth muscle cell proliferation" and "blood coagulation". Moreover, when Young was compared with Middle or Old, "complement and coagulation cascades" was the top enriched pathway by KEGG pathway enrichment analysis. Functional phenotyping of the proteome demonstrated that the plasma proteomic profiles of young adults were strikingly dissimilar to those of the middle-aged or older adults.

CONCLUSIONS

The results of this study mapped the variation in the expression of plasma proteins and provided information about possible biomarkers/treatments for different age-related functional disorders.

A new biased estimation method based on Neumann series for solving ill-posed problems

The ill-posed least squares problems often arise in many engineering applications such as machine learning, intelligent navigation algorithms, surveying and mapping adjustment model, and linear regression model. A new biased estimation (BE) method based on Neumann series is proposed in this article to solve the ill-posed problems more effectively. Using Neumann series expansion, the unbiased estimate can be expressed as the sum of infinite items. When all the high-order items are omitted, the proposed method degenerates into the ridge estimation or generalized ridge estimation method, whereas a series of new biased estimates can be acquired by including some high-order items. Using the comparative analysis, the optimal biased estimate can be found out with less computation. The developed theory establishes the essential relationship between BE and unbiased estimation and can unify the existing unbiased and biased estimate formulas. Moreover, the proposed algorithm suits for not only ill-conditioned equations but also rank-defect equations. Numerical results show that the proposed BE method has improved accuracy over the existing robust estimation methods to a certain extent.

Effects of short-time exposure to atrazine on miRNA expression profiles in the gonad of common carp (Cyprinus carpio)

BACKGROUND

Atrazine is widely used in agriculture and is a known endocrine disrupting chemical. Atrazine can seep into the water body through surface, posing a potential threat to the aquatic ecological environment and human drinking water source. In vertebrate, studies have shown that it can affect reproduction and development seriously, but its molecular mechanism for aquatic animals is unknown. Aquaculture is very common in China, especially common carp, whose females grow faster than males. However, the effects of atrazine on the reproduction of carp, especially miRNA, have not been investigated.

RESULTS

In this study, common carp (Cyprinus carpio) at two key developmental stages were exposed to atrazine in vitro. Sex ratio was observed to analyze the effect of atrazine on the sex. MiRNA expression profiles were analysed to identify miRNAs related to gonad development and to reveal the atrazine mechanisms interfering with gonad differentiation. The results showed that the sex ratio was biased towards females. Atrazine exposure caused significant alteration of multiple miRNAs. Predicted targets of differently-expressed miRNAs were involved in many reproductive biology signalling pathways.

CONCLUSIONS

Our results indicate that atrazine promoted the expression of female-biased genes by decreasing miRNAs in primordial gonad. In addition, our results indicate that atrazine can up-regulate aromatase expression through miRNAs, which supports the hypothesis that atrazine has endocrine-disrupting activity by altering the gene expression profile of the Hypothalamus-Pituitary-Gonad axis through its corresponding miRNAs.

[Analysis on condom use negotiation with sex partners and condom use in female sex workers]

Objective: To know condom use negotiation with clients and regular sex partners and condom use in female sex workers (FSWs), and provide reference for the development of comprehensive HIV/AIDS intervention for FSWs. Methods: The cross sectional survey was conducted in Jianshui county and Mengzi county in Honghe Hani and Yi autonomous prefecture. A total of 476 FSWs aged 16 years and above were recruited from entertainment venues, and the information about their demographic characteristics, condom use negotiation and condom use were collected by using questionnaires. Logistic regression model was used to analyze related factors of condom use after negotiation between FSWs and clients unwilling use condom. Results: A total of 852 FSWs who aged (24.29±8.44) years old participated in the survey. In past month, 499 FSWs had negotiation for condom use with unwilling clients (58.6%, 499/852), after negotiation, 441 FSWs (88.4%, 441/499) had consistent condom use in each sex with the clients. In the past one month, 99 FSWs had negotiation for unwilling use condom with regular sex partners (14.4%, 99/687), after negotiation, 54 FSWs (54.5%, 54/99) had consistent condom use in each sex with regular sex partners. Among the FSWs, 266 (53.3%, 266/499) reported that they could say "It is a mandatory requirement" to persuade clients who were unwilling to use condom. 97(19.4%, 97/499) reported that they could say "There is risk for infection" to persuade clients who were unwilling to use condoms. 115 (23.1%,115/499) reported that they could say "It is a mandatory requirement" and "there is risk for infection" to persuade their unwilling clients to use condoms. 21 (4.2%, 21/499) reported that they used other strategies. 22 (4.4%, 22/499) felt that it was difficult to persuade clients to use condoms. Multivariate logistic regression analysis showed that compared with FSWs who felt difficult in persuading clients to use condoms, FSWs who felt moderate difficulty were more likely to have consistent condom use after negotiation (OR=4.00, 95%CI: 1.55-10.32) and FSWs who felt easy in persuading clients to use condoms were also more likely to have consistent condom use (OR=30.17, 95%CI: 3.22-282.44). Compared with FSWs used other strategies to persuade their clients to use condoms, FSWs who said it was a mandatory requirement were more likely to have consistent condom use after negotiation (OR=4.44, 95%CI: 1.41-14.01) and FSWs who said it was a mandatory requirement and there was risk for infection were also more likely to have consistent condom use (OR=5.52, 95%CI: 1.55-19.73). Conclusions: Negotiation for condom use increased the rate of condom use in FSWs in sex with clients who were unwilling to use condom. The negotiation strategy of "It is a mandatory requirement" would promote condom use in FSWs in sex with clients who were unwilling to use condom. Besides, the negotiation strategy of saying "there is risk for infection" had additional effects.

Selection of suitable candidate genes for miRNA expression normalization in Yellow River Carp (Cyprinus carpio. var)

Yellow River carp is widely cultivated in the world due to its economic value in aquaculture, and the faster growth of females compared to males. It is believed that microRNAs (miRNA) are involved in gonadal differentiation and development. qPCR is the most preferred method for miRNA functional analysis. Reliable reference genes for normalization in qRT-PCR are the key to ensuring the accuracy of this method. The aim of present research was to evaluate as well as identify the efficacy of reference genes for miRNA expression using qRT-PCR in Yellow River carp. Nine ncRNAs (miR-101, miR-23a, let7a, miR-26a, miR-146a, miR-451, U6, 5S, and 18S) were chosen and tested in four sample sets: (1) different tissues in adult carp, (2) different tissues in juvenile carp, (3) different early developmental stages of carp, and (4) different developmental stages of carp gonads. The stability and suitability values were calculated using NormFinder, geNorm, and BestKeeper software. The results showed that 5S was a suitable reference gene in different tissues of adult and juvenile carp. The genes 5S, 18S, and U6 were the most stable reference genes in the early developmental stages of carp. Let-7a and miR-23a were considered as the suitable reference genes in the development of gonads. All these reference genes were subsequently validated using miR-430. The results showed that genes 5S and 18S were the most suitable reference genes to normalize miRNA expression under normal growth conditions in early different developmental stages. The genes Let-7a, and miR-23a were the most suitable in different developmental stages. The present study is the first comprehensive study of the stability of miRNA reference genes in Yellow River carp, providing valuable as well as basic data for investigating more accurate miRNA expression during gonadal differentiation and development of carp.

An eight-channel correlation electron cyclotron emission diagnostic for turbulent electron temperature fluctuation measurement in HL-2A tokamak

A new correlation electron cyclotron emission (CECE) diagnostic has recently been installed on the HL-2A tokamak in order to study electron temperature fluctuations. Eight radial locations are measured simultaneously through eight pairs of correlated channels. Multiplexers are employed in the intermediate frequency section instead of the conventional separated filter banks to meet strict cross-isolation specifications and lower insertion loss. Relative electron temperature fluctuations are observed by CECE for the first time on the HL-2A by using the spectral decorrelation method. The achieved minimum detectable fluctuation level is up to (T̃_e/T_e)_min∼0.5%. When studying electron temperature fluctuations in the core region with gas puffing, the cross-power spectra show that the amplitude of the electron temperature fluctuation increases in a high temperature and low density plasma. Further analysis demonstrates that the electron temperature gradient ∇T_e drives the electron temperature fluctuations together with electron heat transport.

High-sensitivity far-forward collective scattering diagnostic on HL-2A tokamak

The multichannel formic acid (HCOOH, λ = 432.5 µm) laser interferometer and Faraday-effect polarimeter on HL-2A tokamak have been developed to measure the far-forward collective scattering from electron density fluctuations. The far-forward collective scattering system provides eight channels of line-integrated electron density fluctuations, covering the wave-number range: k_⊥ < 1.6 cm^-1. With the new diagnostic, the density fluctuations caused by plasma energetic particles and turbulence have been routinely observed in HL-2A experiments.

[A retrospective analysis of CO(2) laser and microdebrider for the treatment of severe juvenile on-set recurrent respiratory papillomatosis]

Objective: Juvenile on-set recurrent respiratory papillomatosis (JORRP) can be an aggressive and potentially life-threatening disease. To emphasize the importance of complication prevention in local excision surgery, the single-center experience of RRP treatment in a group of patients with relatively short recurrence-free-interval (>4 times/yrs) was reported. Methods: Data of 49 patients underwent papilloma resection during 2002-2013 were retrospectively analyzed. Combined techniques of laser microsurgery and microdebriders were used to remove papillomas, prevent the formation of scar tissue and improve respiratory distress. Forty-nine cases were followed up for 99.0[74.5; 121.0]months, ranging from 39 to 185 months. The age of disease onset was 2[1; 3] years old. Most of the patients had difficulty in breathing(42 of 49 cases). Seven patients had hoarseness.53.0% patients had subglottic or trachea papillomatosis spreading. The rate of complications, synechia formation, tracheal stenosis, needing for tracheostomy, mortality was recorded. Patients were followed up for at least three years. The characteristics of the patients, improvement in symptoms, recurrence-free interval, and the rate of tracheal extubation were evaluated. Wilcoxon signed ranks test and chi-square test were used for data comparation. Results: Long-term relieve in disease(≤2 surgeries were needed/year) were achieved in 29(59.1%) subjects, in which 8(16.3%) of the subjects did not need surgical treatment for at least 3 years. Long-term relieve had been achieved in 25 of subjects who did not accept tracheostomy. Seven subjects did not need surgical treatment for at least 3 years. The rate of successful tracheal extubation was 53.8% in 13 patients who had undergone tracheostomy. Three cases dead of intrapulmonary spread. Conclusions: Combined techniques of laser microsurgery and microdebriders are effective in improvement in both respiratory distress and voice quality. The combined technique are helpful to avoid inevitable long-term stenotic complications, ultimately affecting the quality of life.

Note: Real-time wavelength matching system designed for the motional Stark effect polarimeter on HL-2A tokamak

A 7-channel motional Stark effect diagnostic based on dual photo-elastic modulators is installed and operated routinely for rather low beam energy and magnetic field on the HL-2A tokamak, with a spatial resolution of ∼3 cm and a temporal resolution of 10 ms. The instrument observes the σ component of the full energy D_α from the first or the fourth ion source of a neutral beam injector. However, the change in beam energy during a discharge causes variation of the Doppler shift with the maximum of 1 Å, which leads to the polarization fraction drop from 30%-40% to 10% and then makes the signal-to-noise ratio of the system become very poor. Therefore, a real-time wavelength matching system is designed to promote polarization fraction. The beam emission spectra are filtered by using a monochrometer in real time. And a narrowband filter is tilted by using an absolutely calibrated rotator through beam energy in order to make sure that the deviation of wavelength matching is less than 0.1 Å.

Crystal structure and anti-inflammatory and anaphylactic effects of andrographlide sulphonate E in Xiyanping, a traditional Chinese medicine injection

OBJECTIVES

Andrographlide sulphonate E, namely sodium 9-dehydro-17-hydro-andrographolide-19-yl sulphate, was one of the major ingredients of Xiyanping injection. The present study aimed to demonstrate its suitability as a reference standard for use of quality control of this traditional Chinese medicine preparation made from andrographlide that has been widely used to treat various infectious diseases.

METHODS

The stable crystals were prepared for unambiguous elucidation of the chemical structure by comprehensive spectral and thermal analysis. The anti-inflammatory effects were investigated using in vitro and in vivo methods, and the potential allergenic risk related with safety was evaluated by in silico molecular docking analysis.

KEY FINDINGS

The dihydrated sulphonate derivative could be present as orthorhombic crystals with stable three-dimensional supramolecular structure, providing it the favourable physico-chemical stability as reference substance. It exhibited potent anti-inflammatory activity both in vitro and in vivo, suggesting the potency responsible for clinic efficacy of Xiyanping. Molecular docking further demonstrated its low risk of allergic reaction, as well as the proposed mechanism of anaphylactic effect of andrographolide analogues.

CONCLUSIONS

Dihydrated sodium 9-dehydro-17-hydro-andrographolide-19-yl sulphate may be the ideal reference standard for use in quality control of Xiyanping.

[The expression characteristics and clinical significance of candidate molecular markers in vocal cord leukoplakia]

Objective: To investigate the expression of marker proteins in vocal cord leukoplakia, and to find markers for the early stage of diagnosis and prognosis of precancerous lesions. Methods: The study included 119 cases, 68 cases of vocal cord leukoplakia (22 cases with epithelial simple hyperplasia, 46 cases with epithelial dysplasia), and 51 cases of vocal cords benign lesions(31 cases of vocal cord polyps, 20 cases of Reinke's edema). The expression of p53, Ki-67, p21, Survivin, p16, p27, PTEN, c-Myc and vascular endothelial growth factor (VEGF) in vocal cords leukoplakia were detected, vocal cord benign lesions (vocal cord polyps and Reinke's edema) acted as controls, comparing the expression differences of different pathological tissue. Data was analyzed by SPSS 22.0 software. Results: The expression of p53, p16, Ki-67, VEGF in vocal cord benign lesions and vocal cords leukoplakia with epithelial simple hyperplasia did not show significant differences. There was a grading increase in the positive expression of p53, Ki-67 in the vocal cord leukoplakia with epithelial dysplasia contrasting to those in vocal cord benign lesions and vocal cords leukoplakia with epithelial simple hyperplasia (p53: χ(2)=13.340, P=0.002, Ki-67: χ(2)=53.386, P=0.000). The expression of p27, PTEN, c-Myc in vocal cord benign lesions and vocal cords leukoplakia with epithelial dysplasia did not show significant differences. There was a grading increase in the positive expression of p21 Survivin in vocal cords leukoplakia with epithelial dysplasia contrasting to those in vocal cord benign lesions (P<0.05). Expression of Survivin in vocal cords leukoplakia with mild-moderate epithelial dysplasia showed a significant increase than those in vocal cord benign lesions (P<0.05). The positive expression grade of p21 showed a rising trend (P=0.073) between the different grades of dysplasia. Conclusion: The positive expression grade of p53, Ki-67, p21 Survivin showed an increase in vocal cords leukoplakia with epithelial dysplasia contrasting to those in vocal cord benign lesions, which might be an implication for evaluating the diagnosis and prognosis of precancerous lesions. Expression of p21 was correlated to the degrees of dysplasia and expression of Survivin showed a significant difference in early stage of epithelial dysplasia contrasting to benign lesions.

[Quantitative determination method and application of pharmaceutical adjuvant tween 80]

Based on the fact that chromogenic reaction of blue complex, a reaction product which can be dissolved in organic solvents, can be realized by polyethoxy and ammonium thiocyanate in tween 80, a rapid and accurate way for the determination for tween 80 in pharmaceutical adjuvant was established in this study, providing reliable technical means for quality control of traditional Chinese medicine injections. Based on the study of reaction kinetics, chromogenic reaction temperature and time, as well as extraction of organic solvents and other key conditions were optimized, and Kumu injection was used as the test material for method validation and applicability investigation. It was finally determined that 3 mL ammonium thiocyanate solution was added in the sample solution, and the reaction was carried out in a boiling water bath for 2 h. After cooling to room temperature, 5 mL of dichloromethane was added to extract the chromogenic product. The absorbance value was measured at the wavelength of 623 nm to calculate the tween 80 content in the sample. Under optimized conditions, tween 80 solution showed a good linear relationship with the absorbance in the range from 0.8 mg to 3.0 mg. The linear regression equation was y＝0.258x-0.047. The correlation coefficient r was 0.999 6. Under the experimental conditions, the average recovery was 99.66%, and the precision RSD was less than 2.0%. The results showed that this method can quickly and accurately determine the content of tween 80 in Kumu injection, and it could be applicable to the quality control of traditional Chinese medicine injections.

[Clinical and pathological characteristics of vocal fold leukoplakia and influential factors of recurrence and malignancy]

Objective:To investigate the clinical and pathological characteristics of vocal fold leukoplakia and influential factors of recurrence and malignancy. Method:The study included 555 cases of vocal fold leukoplakia. All patients received surgical treatment. The relationship between the clinical and pathological features, and influential factors of recurrence and malignancy were analyzed. Result:The pathological types included squamous epithelial simple hyperplasia in 58.0%, mild hyperplasia in 15.5%, moderate hyperplasia in 10.1%, severe hyperplasia and carcinoma in situ in 8.1%, infiltrative carcinoma in 8.3%. The different pathological types varied among different ages significantly(P<0.01). The tobacco and alcohol abuse had no relationship with pathological types(P>0.05). The more severe the pathology were, the more decreasing of the mucosal waves would be(P<0.01). The pathologic severity had an apparent correlation with p53 positivity and the level of p53 and Ki67 positivity. The p53 positive proportion may increase with the increasing pathological severity(P<0.01), so were the p53 and Ki67 positive levels(P<0.01).Among 232 cases of postoperation follow-ups, 83 cases(35.8%) relapsed while 8 cases(3.4%) malignancy. Bilateral lesions had a higher rate of relapse and malignancy than unilateral lesions(95%CIOR 0.378 ［0.197-0.723］，P<0.01). The relapse and malignancy had a relationship with the pathologic severity. The incidence of disease recurrence and malignancy were positively correlated with pathological severity(P<0.05). p16 positive patients relapsed for more times(P<0.01) and with an uprising tendency of relapse and malignancy（P>0.05）. Conclusion:Pathological types of vocal fold leukoplakia are different. The older men, decreasing of mucosal wave of vocal folds and bilateral lesions were very important factors to predict disease severity. p53 and Ki67 positive rating and pathological severity were positively correlated. The bilateral lesions, pathological severity and p16 positivity had a tendency to increasing relapse and malignancy.

Bayesian tomography and integrated data analysis in fusion diagnostics

In this article, a Bayesian tomography method using non-stationary Gaussian process for a prior has been introduced. The Bayesian formalism allows quantities which bear uncertainty to be expressed in the probabilistic form so that the uncertainty of a final solution can be fully resolved from the confidence interval of a posterior probability. Moreover, a consistency check of that solution can be performed by checking whether the misfits between predicted and measured data are reasonably within an assumed data error. In particular, the accuracy of reconstructions is significantly improved by using the non-stationary Gaussian process that can adapt to the varying smoothness of emission distribution. The implementation of this method to a soft X-ray diagnostics on HL-2A has been used to explore relevant physics in equilibrium and MHD instability modes. This project is carried out within a large size inference framework, aiming at an integrated analysis of heterogeneous diagnostics.

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.

The supersonic molecular beam injector as a reliable tool for plasma fueling and physics experiment on HL-2A

On HL-2A tokamak, supersonic molecular beam injection (SMBI) has been developed as a routine refueling method. The key components of the system are an electromagnetic valve and a conic nozzle. The valve and conic nozzle are assembled to compose the simplified Laval nozzle for generating the pulsed beam. The appurtenance of the system includes the cooling system serving the cooled SMBI generation and the in situ calibration component for quantitative injection. Compared with the conventional gas puffing, the SMBI features prompt response and larger fueling flux. These merits devote the SMBI a good fueling method, an excellent plasma density feedback control tool, and an edge localized mode mitigation resource.

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.

Evaluation of the stability of reference genes in bone mesenchymal stem cells from patients with avascular necrosis of the femoral head

This study aimed to evaluate 12 genes (18S, GAPDH, B2M, ACTB, ALAS1, GUSB, HPRT1, PBGD, PPIA, PUM1, RPL29, and TBP) for their reliability and stability as reference sequences for real-time quantitative PCR (RT-qPCR) in bone marrow-derived mesenchymal stem cells (BMSCs) isolated from patients with avascular necrosis of the femoral head (ANFH). BMSCs were isolated from 20 ANFH patients divided into four groups according to etiology, and four donors with femoral neck fractures. Total RNA was isolated from BMSCs and reverse transcribed into complementary DNA, which served as a template for RT-qPCR. Three commonly used programs were then used to analyze the results. Reference gene expression varied within each group, between specific groups, and among all five groups. Based on comparisons of all five groups, two of the programs used suggested that HPRT1 was the most stable reference gene, while 18S and ACTB were the most variable. Among the 12 candidate reference genes, HPRT1 exhibited the greatest reliability, followed by PPIA. Thus, these sequences could be used as references for the normalization of RT-qPCR results.

Note: Upgrade of electron cyclotron emission imaging system and preliminary results on HL-2A tokamak

The electron cyclotron emission imaging system on the HL-2A tokamak has been upgraded to 24 (poloidally) × 16 (radially) channels based on the previous 24 × 8 array. The measurement region can be flexibly shifted due to the independence of the two local oscillator sources, and the field of view can be adjusted easily by changing the position of the zoom lenses. The temporal resolution is about 2.5 μs and the achievable spatial resolution is 1 cm. After laboratory calibration, it was installed on HL-2A tokamak in 2014, and the local 2D mode structures of MHD activities were obtained for the first time.

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.

Progress of neutral-beam-aided diagnostics on the HL-2A tokamak

A 32/64-channel Charge eXchange Recombination Spectroscopy (CXRS) and a 7-channel motional Stark effect (MSE) polarimeter have been developed on the HL-2A tokamak. To extract the maximum time resolution of the system, the incidence fibers of the spectrometer are pitch-controlled; and the double-slit fiber bundle can increase the spatial channels with one charge-coupled device detector. The ion temperature and plasma rotation with time and spatial resolutions up to 5 ms and 1 cm are obtained. Sawtooth oscillation, transition from intermediate phase (I phase) to high confinement mode (H mode) can be clearly observed by the CXRS. The spectrometer can be utilized as the main component of the MSE polarimeter, which can effectively overcome the weak Stark effect. The pitch angles of magnetic field are obtained for 7 spatial points covering 24 cm along major radius with time resolution of 40 ms.

High spatial and temporal resolution charge exchange recombination spectroscopy on the HL-2A tokamak

A 32/64-channel charge exchange recombination spectroscopy (CXRS) diagnostic system is developed on the HL-2A tokamak (R = 1.65 m, a = 0.4 m), monitoring plasma ion temperature and toroidal rotation velocity simultaneously. A high throughput spectrometer (F/2.8) and a pitch-controlled fiber bundle enable the temporal resolution of the system up to 400 Hz. The observation geometry and an optimized optic system enable the highest radial resolution up to ∼1 cm at the plasma edge. The CXRS system monitors the carbon line emission (C VI, n = 8-7, 529.06 nm) whose Doppler broadening and Doppler shift provide ion temperature and plasma rotation velocity during the neutral beam injection. The composite CX spectral data are analyzed by the atomic data and analysis structure charge exchange spectroscopy fitting (ADAS CXSFIT) code. First experimental results are shown for the case of HL-2A plasmas with sawtooth oscillations, electron cyclotron resonance heating, and edge transport barrier during the high-confinement mode (H-mode).

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.

Development of the scintillator-based probe for fast-ion losses in the HL-2A tokamak

A new scintillator-based lost fast-ion probe (SLIP) has been developed and operated in the HL-2A tokamak [L. W. Yan, X. R. Duan, X. T. Ding, J. Q. Dong, Q. W. Yang, Yi Liu, X. L. Zou, D. Q. Liu, W. M. Xuan, L. Y. Chen, J. Rao, X. M. Song, Y. Huang, W. C. Mao, Q. M. Wang, Q. Li, Z. Cao, B. Li, J. Y. Cao, G. J. Lei, J. H. Zhang, X. D. Li, W. Chen, J. Chen, C. H. Cui, Z. Y. Cui, Z. C. Deng, Y. B. Dong, B. B. Feng, Q. D. Gao, X. Y. Han, W. Y. Hong, M. Huang, X. Q. Ji, Z. H. Kang, D. F. Kong, T. Lan, G. S. Li, H. J. Li, Qing Li, W. Li, Y. G. Li, A. D. Liu, Z. T. Liu, C. W. Luo, X. H. Mao, Y. D. Pan, J. F. Peng, Z. B. Shi, S. D. Song, X. Y. Song, H. J. Sun, A. K. Wang, M. X. Wang, Y. Q. Wang, W. W. Xiao, Y. F. Xie, L. H. Yao, D. L. Yu, B. S. Yuan, K. J. Zhao, G. W. Zhong, J. Zhou, J. C. Yan, C. X. Yu, C. H. Pan, Y. Liu, and the HL-2A Team, Nucl. Fusion 51, 094016 (2011)] to measure the losses of neutral beam ions. The design of the probe is based on the concept of the α-particle detectors on Tokamak Fusion Test Reactor (TFTR) using scintillator plates. The probe is capable of traveling across an equatorial plane port and sweeping the aperture angle rotationally with respect to the axis of the probe shaft by two step motors, in order to optimize the radial position and the collimator angle. The energy and the pitch angle of the lost fast ions can be simultaneously measured if the two-dimensional image of scintillation light intensity due to the impact of the lost fast ions is detected. Measurements of the fast-ion losses using the probe have been performed during HL-2A neutral beam injection discharges. The clear experimental evidence of enhanced losses of beam ions during disruptions has been obtained by means of the SLIP system. A detailed description of the probe system and the first experimental results are reported.

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.

Calibration of a 32 channel electron cyclotron emission radiometer on the HL-2A tokamak

A novel 32-channel electron cyclotron emission radiometer has been designed and tested for the measurement of electron temperature profiles on the HL-2A tokamak. This system is based on the intermediate frequency filter detection technique, and has the features of wide working frequency range and high spatial resolution. Two relative calibration methods have been investigated: sweeping the toroidal magnetic field and hopping the output frequency of the local oscillator. Preliminary results show that both methods can ensure reasonable profiles.

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).

Minimum Fisher regularization of image reconstruction for infrared imaging bolometer on HL-2A

An infrared imaging bolometer diagnostic has been developed recently for the HL-2A tokamak to measure the temporal and spatial distribution of plasma radiation. The three-dimensional tomography, reduced to a two-dimensional problem by the assumption of plasma radiation toroidal symmetry, has been performed. A three-dimensional geometry matrix is calculated with the one-dimensional pencil beam approximation. The solid angles viewed by the detector elements are taken into account in defining the chord brightness. And the local plasma emission is obtained by inverting the measured brightness with the minimum Fisher regularization method. A typical HL-2A plasma radiation model was chosen to optimize a regularization parameter on the criterion of generalized cross validation. Finally, this method was applied to HL-2A experiments, demonstrating the plasma radiated power density distribution in limiter and divertor discharges.

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.

Antigenic and immunogenic characterization of infectious bronchitis virus strains isolated in China between 1986 and 1995

Eight strains of infectious bronchitis virus (IBV) were isolated between 1986 and 1995 from broilers and layers at eight different farms in four provinces in China. The viruses were isolated from flocks which suffered from either respiratory disease or nephritis and the majority had not been vaccinated against IBV. Six strains were shown by monoclonal antibodies to differ from H120, Connecticut and Arkansas 99 strains of IBV and also to differ from each other. Four of these strains were serotyped; one (NRZ) was of the Massachusetts serotype, three (HV, NB-90 and TJ) shared a degree of antigenic similarity and were of a serotype that differed from Massachusetts and Connecticut. NB-90 was similar to both Gray and T strains whereas TJ shared some similarity with the T strain. Four strains, HV, NB-90, YY and TJ induced 33, 47, 60 and 90% mortality, respectively, in 3-week-old specific pathogen-free chickens. Clinical signs and post-mortem findings were identical to those induced by the nephropathogenic T strain. Chickens vaccinated with H120 strain, and then challenged with four highly pathogenic strains HV, NB-90, YY and TJ were not protected as determined by both virus isolation and mortality. The results show that highly pathogenic IBV strains which induce clinical nephritis occur frequently in poultry flocks in China. They also confirm field observations on the lack of protection by currently used IB vaccines of the Massachusetts serotype against challenge with these nephropathogenic strains.