Advancement of highly charged ion beam production by superconducting ECR ion source SECRAL (invited)

At Institute of Modern Physics (IMP), Chinese Academy of Sciences (CAS), the superconducting Electron Cyclotron Resonance (ECR) ion source SECRAL (Superconducting ECR ion source with Advanced design in Lanzhou) has been put into operation for about 10 years now. It has been the main working horse to deliver intense highly charged heavy ion beams for the accelerators. Since its first plasma at 18 GHz, R&D work towards more intense highly charged ion beam production as well as the beam quality investigation has never been stopped. When SECRAL was upgraded to its typical operation frequency 24 GHz, it had already showed its promising capacity of very intense highly charged ion beam production. And it has also provided the strong experimental support for the so called scaling laws of microwave frequency effect. However, compared to the microwave power heating efficiency at 18 GHz, 24 GHz microwave heating does not show the ω(2) scale at the same power level, which indicates that microwave power coupling at gyrotron frequency needs better understanding. In this paper, after a review of the operation status of SECRAL with regard to the beam availability and stability, the recent study of the extracted ion beam transverse coupling issues will be discussed, and the test results of the both TE01 and HE11 modes will be presented. A general comparison of the performance working with the two injection modes will be given, and a preliminary analysis will be introduced. The latest results of the production of very intense highly charged ion beams, such as 1.42 emA Ar(12+), 0.92 emA Xe(27+), and so on, will be presented.

24 GHz microwave mode converter optimized for superconducting ECR ion source SECRAL

Over-sized round waveguide with a diameter about Ø33.0 mm excited in the TE01 mode has been widely adopted for microwave transmission and coupling to the ECR (Electron Cyclotron Resonance) plasma with the superconducting ECR ion sources operating at 24 or 28 GHz, such as SECRAL and VENUS. In order to study the impact of different microwave modes on ECRH (Electron Cyclotron Resonance Heating) efficiency and especially the production of highly charged ions, a set of compact and efficient TE01-HE11 mode conversion and coupling system applicable to 24 GHz SECRAL whose overall length is 330 mm has been designed, fabricated and tested. Good agreements between off-line tests and calculation results have been achieved, which indicates the TE01-HE11 converter meets the application design. The detailed results of the optimized coupling system will be presented in the paper.

Ambient volatile organic compounds and their effect on ozone production in Wuhan, central China

Ambient volatile organic compounds (VOCs) were continuously measured from February 2013 to October 2014 at an urban site in Wuhan. The characteristics and sources of VOCs and their effect on ozone (O3) formation were studied for the first time. The total VOC levels in Wuhan were relatively low, and of all VOCs, ethane (5.2 ± 0.2 ppbv) was the species with the highest levels. Six sources, i.e., vehicular exhausts, coal burning, liquefied petroleum gas (LPG) usage, the petrochemical industry, solvent usage in dry cleaning/degreasing, and solvent usage in coating/paints were identified, and their contributions to the total VOCs were 27.8 ± 0.9%, 21.8 ± 0.8%, 19.8 ± 0.9%, 14.4 ± 0.9%, 8.5 ± 0.5%, and 7.7 ± 0.4%, respectively. Model simulation of a photochemical box model incorporating the Master Chemical Mechanism (PBM-MCM) indicated that the contribution to O3 formation of the above sources was 23.4 ± 1.3%, 22.2 ± 1.2%, 23.1 ± 1.7%, 11.8 ± 0.9%, 5.2 ± 0.4%, and 14.2 ± 1.1%, respectively. LPG and solvent usage in coating/paints were the sources that showed higher contributions to O3 formation, compared to their contributions to VOCs. The relative incremental reactivity (RIR) analysis revealed that the O3 formation in Wuhan was generally VOC-limited, and ethene and toluene were the primary species contributing to O3 production, accounting for 34.3% and 31.5% of the total RIR-weighted concentration, respectively. In addition, the contribution of CO to the O3 formation was remarkable. The C4 alkanes and alkenes from the LPG usage also significantly contributed to the O3 formation. The results can assist local governments in formulating and implementing control strategies for photochemical pollution.

Effects of microwave ablation or its combination with whole-body chemotherapy on serum vascular endothelial growth factor levels in patients with stage IIIB/IV NSCLC

We aimed to analyze the changes of serum vascular endothelial growth factor (VEGF) before and after microwave ablation (MWA) in patients with stage IIIB-IV non-small cell lung cancer (NSCLC), and to observe the effects of MWA combined with chemotherapy on short-term therapeutic efficacy and long-term survival. Concentrations of serum VEGF in 20 healthy subjects were considered as controls. Changes of serum VEGF were detected by ELISA before and after MWA (1 and 7 days after treatment). Seven days after MWA, patients were divided into a combination chemotherapy group of 22 subjects and a MWA alone group of 18 subjects. Serum VEGF was measured 1 month after MWA and 4 cycles after chemotherapy (3 months) to evaluate term effects; and 1- and 2-year survival rates. Serum VEGF concentrations declined sharply 1 day after MWA, and were significantly different from the levels before treatment. Subsequently, VEGF rebounded 7 days after ablation, higher than that before treatment. At 1 and 3 months, serum VEGF levels in both treatment groups were remarkably lower than that before treatment; efficiency, or for the 1-year survival rate. However, the 2-year survival rates were significantly different between the two groups. We demonstrated that after MWA, the serum VEGF concentration undergoes a process of increasing, which might promote metastasis and recurrence of NSCLC. MWA combined with whole-body chemotherapy appears to be an effective method to increase the disease control rate, reduce the probability of metastasis and recurrence, and thus improve long-term survival.

Studies on a Q/A selector for the SECRAL electron cyclotron resonance ion source

Electron cyclotron resonance ion sources are widely used in heavy ion accelerators in the world because they are capable of producing high current beams of highly charged ions. However, the design of the Q/A selector system for these devices is challenging, because it must have a sufficient ion resolution while controlling the beam emittance growth. Moreover, this system has to be matched for a wide range of ion beam species with different intensities. In this paper, research on the Q/A selector system at the SECRAL (Superconducting Electron Cyclotron Resonance ion source with Advanced design in Lanzhou) platform both in experiment and simulation is presented. Based on this study, a new Q/A selector system has been designed for SECRAL II. The features of the new design including beam simulations are also presented.

Neuroprotection effect of interleukin (IL)-17 secreted by reactive astrocytes is emerged from a high-level IL-17-containing environment during acute neuroinflammation

An increase in interleukin (IL)-17A-producing cells, particularly at sites of tissue inflammation, is observed frequently, yet the mechanism is not fully understood. This study aims to dissect the role of IL-17 in autoimmunity-mediated neuroinflammation. The cytokine milieu containing elevated IL-17, which often appears in active states of autoimmunity, was mimicked in vitro by a supernatant obtained from rat peripheral blood monocytes stimulated with phorbol mystistate acetate (PMA)/ionomycin. The application of such inflammatory media on only primary cultured cerebellar granule neurones resulted in significant apoptosis, but the presence of astrocytes largely prevented the effect. The supernatants of the stimulated astrocytes, especially those that contained the highest level of IL-17, achieved the best protection, and this effect could be blocked by anti-IL-17 antibodies. Protein IL-17 inhibited intracellular calcium increase and protected the neurones under inflammatory attack from apoptosis. IL-17, but not interferon (IFN)-γ, in the inflammatory media contributed to astrocyte secretion of IL-17, which depended on the Janus kinase/signal transducers and activators of transcription (JAK/STAT) pathway activation. The astrocytes that were treated with IL-17 alone or with prolonged treatment of the inflammatory media failed to produce sufficient levels of IL-17. Moreover, confirmatory data were obtained in vivo in a monophasic experimental autoimmune uveitis (EAU) in Lewis rats; in this preparation, the high-level IL-17-containing the cytokine milieu was demonstrated, along with IL-17 secretion by the resident neural cells. The antagonism of IL-17 at a late stage disturbed the disease resolution and resulted in significant neural apoptosis. Our data show a dynamic role of IL-17 in the maintenance of homeostasis and neuroprotection in active neuroinflammation.

Progress of superconducting electron cyclotron resonance ion sources at Institute of Modern Physics (IMP)

Superconducting ECR ion sources can produce intense highly charged ion beams for the application in heavy ion accelerators. Superconducting Electron Resonance ion source with Advanced Design (SECRAL) is one of the few fully superconducting ECR ion sources that has been successfully built and put into routine operation for years. With enormous efforts and R&D work, promising results have been achieved with the ion source. Heated by the microwave power from a 7 kW/24 GHz gyrotron microwave generator, very intense highly charged gaseous ion beams have been produced, such as 455 eμA Xe(27+), 236 eμA Xe(30+), and 64 eμA Xe(35+). Since heavy metallic ion beams are being more and more attractive and important for many accelerator projects globally, intensive studies have been made to produce highly charged heavy metal ion beams, such as those from bismuth and uranium. Recently, 420 eμA Bi(30+) and 202 eμA U(33+) have been produced with SECRAL source. This paper will present the latest results with SECRAL, and the operation status will be discussed as well. An introduction of recently started SECRAL II project will also be given in the presentation.

A low energy beam transport system for proton beam

A low energy beam transport (LEBT) system has been built for a compact pulsed hadron source (CPHS) at Tsinghua University in China. The LEBT, consisting of two solenoids and three short-drift sections, transports a pulsed proton beam of 60 mA of energy of 50 keV to the entrance of a radio frequency quadrupole (RFQ). Measurement has shown a normalized RMS beam emittance less than 0.2 π mm mrad at the end of the LEBT. Beam simulations were carried out to compare with the measurement and are in good agreement. Based on the successful CPHS LEBT development, a new LEBT for a China ADS projector has been designed. The features of the new design, including a beam chopper and beam simulations of the LEBT are presented and discussed along with CPHS LEBT development in this article.

Determinants of nonurgent use of the emergency department for pediatric patients in 12 hospitals in Belgium

INTRODUCTION

The nonurgent use of the emergency department (ED) for pediatric patients is an increasing problem facing healthcare systems worldwide. To evaluate the magnitude of the phenomenon and to identify associated factors, an observational prospective survey was performed including all patients (<15 years) attending the ED in 12 Belgian hospitals during 2 weeks in autumn 2010. Use of ED was considered appropriate if at least one of the following criteria was met: child referred by doctor or police, brought by ambulance, in need for short stay, technical examination or orthopedic treatment, in-patient admission, or death. Among the 3,117 children, attending ED, 39.9 % (1,244) of visits were considered inappropriate. Five factors were significantly associated with inappropriate use: age of child, distance to ED, having a registered family doctor, out-of-hours visit, and geographic region. The adjusted odds ratio and 95 % confidence intervals are respectively-1.7 (1.3-2.0), 1.7 (1.3-2.2), 1.5 (1.1-2.2), 1.5 (1.2-1.9), and 0.6 (0.5-0.8).

CONCLUSIONS

Almost 40 % of all paediatric ED attendances did not require hospital expertise. The risk of an inappropriate use of ED by pediatrician patients is predominantly associated with organizational and cultural factors. Access, equity, quality of care, and medical human resources availability have to be taken into account to design financially sustainable model of care for those patients. Furthermore, future research is needed to explain reasons why parents visit ED rather than using of primary-care services.

Development of DRAGON electron cyclotron resonance ion source at Institute of Modern Physics

A new room temperature electron cyclotron resonance (ECR) ion source, DRAGON, is under construction at IMP. DRAGON is designed to operate at microwaves of frequencies of 14.5-18 GHz. Its axial solenoid coils are cooled with evaporative medium to provide an axial magnetic mirror field of 2.5 T at the injection and 1.4 T at the extraction, respectively. In comparison to other conventional room temperature ECR ion sources, DRAGON has so far the largest bore plasma chamber of inner diameter of 126 mm with maximum radial fields of 1.4-1.5 T produced by a non-Halbach permanent sextupole magnet.

Status of the laser ion source at IMP

A laser (Nd:YAG laser, 3 J, 1064 nm, 8-10 ns) ion source has been built and under development at IMP to provide pulsed high-charge-state heavy ion beams to a radio frequency quadrupole (RFQ) for upgrading the IMP accelerators with a new low-energy beam injector. The laser ion source currently operates in a direct plasma injection scheme to inject the high charge state ions produced from a solid target into the RFQ. The maximum power density on the target was about 8.4 × 10(12) W∕cm(2). The preliminary experimental results will be presented and discussed in this paper.

A 2.45 GHz electron cyclotron resonance proton ion source and a dual-lens low energy beam transport

The structure and preliminary commissioning results of a new 2.45 GHz ECR proton ion source and a dual-lens low energy beam transport (LEBT) system are presented in this paper. The main magnetic field of the ion source is provided by a set of permanent magnets with two small electro-solenoid magnets at the injection and the extraction to fine tune the magnetic field for better microwave coupling. A 50 keV pulsed proton beam extracted by a three-electrode mechanism passes through the LEBT system of length of 1183 mm. This LEBT consists of a diagnosis chamber, two Glaser lenses, two steering magnets, and a final beam defining cone. A set of inner permanent magnetic rings is embedded in each of the two Glaser lenses to produce a flatter axial-field to reduce the lens aberrations.

Study of ion beam transport from the SECRAL electron cyclotron resonance ion source at the Institute of Modern Physics

Ion beam transport from the Superconducting Electron Cyclotron Resonance ion source with Advanced design in Lanzhou (SECRAL) electron cyclotron resonance ion source was studied at the Institute of Modern Physics during 2010. Particle-in-cell simulations and experimental results have shown that both space charge and magnetic aberrations lead to a larger beam envelope and emittance growth. In the existing SECRAL extraction beam line, it has been shown that raising the solenoid lens magnetic field reduces aberrations in the subsequent dipole and results in lower emittance. Detailed beam emittance measurements are presented in this paper.

Dietary sodium butyrate alleviates the oxidative stress induced by corticosterone exposure and improves meat quality in broiler chickens

The present study was to investigate the effects of dietary microencapsulated sodium butyrate (SB) and acute pre-slaughter stress, mimicked by subcutaneous corticosterone (CORT) administration, on BW, carcass characteristics, muscle antioxidant status, and meat quality of broiler chickens. A total of 120 1-d-old broiler chickens were fed a control diet (without SB) or a 0.4-g microencapsulated SB/kg diet. On 42 d, half of the birds from each treatment were given 1 single subcutaneous injection of CORT (4 mg/kg of BW in corn oil) to mimic acute stress, whereas the other half were injected with the same amount of corn oil (sham control). Three hours later, BW loss was determined and breast meat samples were collected. The results showed that the BW of the CORT-challenged groups lost much more than the sham control group (P < 0.001), whereas it was alleviated by the dietary microencapsulated SB (P < 0.05). Meanwhile, the catalase activity was decreased and malondialdehyde level was increased by the stress (P < 0.05), and the microencapsulated-SB diet significantly inhibited this effect (P < 0.05). Lower pH values and higher yellowness values were also observed in CORT-challenged chickens (P < 0.05), and the microencapsulated-SB diet treatment partially exerted a preventive effect. Microencapsulated SB significantly decreased the contents of saturated fatty acids and C18:0 (P < 0.01 and P < 0.001), and increased C20:0 and C20:4 contents. However, the effect of the stress treatment on fatty acid composition was insignificant (P > 0.05). In addition, diet and stress did not significantly influence carcass characteristics and the chemical composition of breast meat (P > 0.05). These results suggest that microencapsulated SB was favorable for chickens in the presence of stress, which may be partially ascribed to the ability of SB to decrease catabolism and oxidative injury of tissues.

Reversible ferromagnetism study in un-doped ZnO thin films

Room temperature ferromagnetism in pure ZnO thin films prepared by spin-coating method was observed. X-ray photoelectron spectroscopy and inductively coupled plasma-mass spectrometry showed no or extremely little presence of impurities, which were unlikely to be responsible for the large magnetization moment observed. In order to study the origin of ferromagnetism, ZnO thin films were rapidly annealed in N2 and O2 ambient in a repetitive way. Electrical and magnetic performance after each annealing was measured. It is found that ferromagnetism is diminished and re-appeared, in accordance with the decrease and increase of conductivity. Cathodoluminescence spectra show evidence of reversible variation of oxygen vacancy defect in the annealing process. These results provide strong evidence that oxygen vacancies play a significant role in inducing ferromagnetism in ZnO thin films.

Sodium butyrate maintains growth performance by regulating the immune response in broiler chickens

1. The experiment was conducted to investigate the effects of dietary sodium butyrate on the growth performance and immune response of broiler chickens. In experiment 1, 240 1-d-old chickens were allocated into 4 dietary groups (0, 0·25, 0·50 or 1·00 g sodium butyrate/kg) with 6 replicates each. In experiment 2, 120 1-d-old chickens were fed a control diet (without sodium butyrate) or 1·00 g sodium butyrate/kg diet. Half of the chickens fed on each diet were injected intra-peritoneally with 0·5 g/kg body weight of Escherichia coli lipopolysaccharide (LPS) at 16, 18 and 20 d of age. 2. There was no effect of dietary sodium butyrate on growth performance. On d 21, serum interleukin-6 (IL-6) and tumour necrosis factor-alpha (TNF-α) were decreased in chickens given 1·00 g sodium butyrate/kg, serum superoxide dismutase (SOD) and catalase activities were significantly increased, and malondialdehyde (MDA) was decreased by dietary sodium butyrate at 0·50 or 1·00 g/kg. On d 42, serum IL-6 was markedly decreased by dietary sodium butyrate, while 1·00 g sodium butyrate/kg greatly reduced MDA and increased catalase. 3. LPS challenge significantly reduced the growth performance of chickens. Serum IL-1β, IL-6, TNF-α, corticosterone, alpha-1 acid glycoprotein (AGP) and prostaglandin E(2) (PGE(2)) were increased in LPS-challenged chickens. Dietary sodium butyrate supplementation maintained the body weight gain and feed intake. Sodium butyrate supplementation inhibited the increase in IL-6 and AGP in serum at 16 d of age and TNF-α, corticosterone, AGP and PGE(2) at 20 d of age. Similar inhibitory effects of sodium butyrate in serum glucose and total protein concentrations were also found at 20 d of age. 4. The results indicated that dietary sodium butyrate supplementation can improve the growth performance in chickens under stress and that this may be used to moderate the immune response and reduce tissue damage.

Functional recovery after transplantation of neural stem cells modified by brain-derived neurotrophic factor in rats with cerebral ischaemia

Functional recovery after transplantation of brain-derived neurotrophic factor (BDNF)-modified neural stem cells (NSCs) was evaluated in a rat model of cerebral ischaemia damage induced by temporary middle cerebral artery occlusion (tMCAO). Western blotting and enzyme-linked immunosorbent assay demonstrated upregulated BDNF protein expression by rat embryonic NSCs transfected with the human BDNF gene (BDNF-NSCs). BDNF-NSCs stimulated neurite outgrowth in cocultured dorsal root ganglion neurons, suggesting that BDNF increased neurogenesis in vitro. In vivo, BDNF promoted recovery of tMCAO. Phosphate-buffered saline, untransformed NSCs or BDNF-NSCs were introduced into the penumbra zone of the right striatum of tMCAO rats and neurological function deficit was assessed for up to 12 weeks using the neurological severity score (NSS). The NSS was significantly lower in the BDNF-NSC transfected transplant group than in all the other groups from week 10. BDNF-NSCs recovered 1 week after transplantation expressed BDNF protein. Transplanted NSCs had differentiated into mature neurons 12 weeks after transplantation. Transgenic NSCs have potential as a therapeutic agent for brain ischaemia.

The identification of aluminium-resistance genes provides opportunities for enhancing crop production on acid soils

Acid soils restrict plant production around the world. One of the major limitations to plant growth on acid soils is the prevalence of soluble aluminium (Al(3+)) ions which can inhibit root growth at micromolar concentrations. Species that show a natural resistance to Al(3+) toxicity perform better on acid soils. Our understanding of the physiology of Al(3+) resistance in important crop plants has increased greatly over the past 20 years, largely due to the application of genetics and molecular biology. Fourteen genes from seven different species are known to contribute to Al(3+) tolerance and resistance and several additional candidates have been identified. Some of these genes account for genotypic variation within species and others do not. One mechanism of resistance which has now been identified in a range of species relies on the efflux of organic anions such as malate and citrate from roots. The genes controlling this trait are members of the ALMT and MATE families which encode membrane proteins that facilitate organic anion efflux across the plasma membrane. Identification of these and other resistance genes provides opportunities for enhancing the Al(3+) resistance of plants by marker-assisted breeding and through biotechnology. Most attempts to enhance Al(3+) resistance in plants with genetic engineering have targeted genes that are induced by Al(3+) stress or that are likely to increase organic anion efflux. In the latter case, studies have either enhanced organic anion synthesis or increased organic anion transport across the plasma membrane. Recent developments in this area are summarized and the structure-function of the TaALMT1 protein from wheat is discussed.

Nitric oxide is involved in phosphorus deficiency-induced cluster-root development and citrate exudation in white lupin

*White lupin (Lupinus albus) forms specialized cluster roots characterized by exudation of organic anions under phosphorus (P) deficiency. Here, the role of nitric oxide (NO) in P deficiency-induced cluster-root formation and citrate exudation was evaluated. *White lupin plants were treated with the NO donor sodium nitroprusside (SNP) and scavenger or inhibitor of NO synthase under conditions of P deficiency (0 muM) or P sufficiency (50 muM). *Phosphorus deficiency enhanced NO production in primary and lateral root tips, with a greater increase in cluster roots than in noncluster roots. NO concentrations decreased with cluster root development from the pre-emergent stage, through the juvenile stage, to the mature stage. The P deficiency-induced increase in NO production was inhibited by antagonists of NO synthase and xanthine oxidoreductase, suggesting the involvement of these enzymes in NO production. SNP markedly increased the number of cluster roots. Citrate exudation from different root segments in P-deficient roots was positively correlated with endogenous root NO concentrations. *These findings demonstrate differential patterns of NO production in white lupin, depending on root zone, developmental stage and P nutritional status. NO appears to play a regulatory role in the formation of cluster roots and citrate exudation in white lupin under conditions of P deficiency.

Use of an expanded gold standard to estimate the accuracy of colposcopy and visual inspection with acetic acid

We estimate the accuracy of colposcopy and visual inspection with acetic acid (VIA) while minimizing the effects of misclassification bias, and maximizing ascertainment of disease. VIA was performed by experienced physicians on a population-based sample of women aged 30 to 49 years in rural Shanxi province, China. Each woman received VIA, liquid-based cytology (LBC) and hybrid capture 2 (hc2, QIAGEN, Gaithersburg, MD; formerly Digene Corporation). Any woman who tested positive on any test had colposcopy, endocervical curettage (ECC) with directed biopsies as necessary and 4-quadrant random biopsies from normal-appearing areas of the cervix. A standard diagnosis based on colposcopy and directed biopsy, and an expanded diagnosis including ECC and 4-quadrant random biopsy were generated for each woman. In 1,839 women, use of the expanded versus the standard diagnostic criteria increased the prevalence of histologically confirmed high-grade cervical intraepithelial neoplasia and cancer (CIN2+) from 3.2% (59/1,839) to 4.2% (77/1,839) and decreased the sensitivity of VIA for CIN2+ from 69.5% (95% CI: 56.8-79.8) to 58.4% (95% CI: 47.3-68.8%) with little change in specificity of approximately 89%. Compared with the expanded diagnostic criterion, the sensitivity of a visual diagnosis of high-grade CIN or cancer by a colposcopist was 49.4% (95% CI: 38.2-60.5). The use of an expanded diagnostic criterion in this study yielded more conservative estimates of the sensitivity of VIA and colposcopy.