Intense Ion Research Articles

Tissue Imprinting on 2D Nanoflakes-Capped Silicon Nanowires for Lipidomic Mass Spectrometry Imaging and Cancer Diagnosis.

Spatially resolved tissue lipidomics is essential for accurate intraoperative and postoperative cancer diagnosis by revealing molecular information in the tumor microenvironment. Matrix-free laser desorption ionization mass spectrometry imaging (LDI-MSI) is an emerging attractive technology for label-free visualization of metabolites distributions in biological specimens. However, the development of LDI-MSI technology that could conveniently and authentically reveal molecular distribution on tissue samples is still a challenge. Herein, we present a tissue imprinting technology by retaining tissue lipids on 2D nanoflakes-capped silicon nanowires (SiNWs) for further mass spectrometry imaging and cancer diagnosis. The 2D nanoflakes were prepared by liquid exfoliation of molybdenum disulfide (MoS2) with nitrogen-doped graphene quantum dots (NGQDs), which serve as both intercalation agent and dispersant. The obtained NGQD@MoS2 nanoflakes were then decorated on the tip of vertical SiNWs, forming a hybrid NGQD@MoS2/SiNWs nanostructure, which display excellent lipid extraction ability, enhanced LDI efficiency and molecule imaging capability. The peak number and total ion intensity of different lipids species on animal lung tissues obtained by tissue imprinting LDI-MSI on NGQD@MoS2/SiNWs were ∼4-5 times greater than those on SiNWs substrate. As a proof-of-concept demonstration, the NGQD@MoS2/SiNWs nanostructure was further applied to visualize phospholipids on sliced non small cell lung cancer (NSCLC) tissue along with the adjacent normal tissue. On the basis of selected feature lipids and machine learning algorithm, a prediction model was constructed to discriminate NSCLC tissues from the adjacent normal tissues with an accuracy of 100% for the discovery cohort and 91.7% for the independent validation cohort.

Onc201 reduces osteoclastogenesis and prevents ovariectomy-induced bone loss via inhibiting RANKL-induced NFATc1 activation and the integrin signaling pathway

Osteoporosis is an osteolytic disease with a disrupted balance between the resorption and formation of bone as well as bone microstructure degeneration, leading to bone loss and increased fracture risk, which greatly affects patients’ quality of life. Currently, inhibition of osteoclast bone resorption remains the mainstream treatment for osteoporosis. Onc201, a new compound, induces the gene expression of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) and has an efficient anticancer effect in clinical trials. However, its effects on osteolytic disease and the mechanism of action are unclear. We examined the effect of Onc201 on nuclear factor κB ligand-receptor activator (RANKL)-induced osteoclasts via Cell Counting Kit-8, bone resorption assay, luciferase reporter assay, immunofluorescence staining, calcium ion intensity assay and employed an ovariectomy model to investigate the effect of Onc201 on osteoporosis in the mice. Results showed that Onc201 inhibited the function and formation of osteoclasts induced by RANKL in a manner that was dependent on time and concentration, and did not cause cytotoxicity. Mechanistically, Onc201 inhibited osteoclast-relevant genes and NFATc1 expression, the main transcriptional regulatory factor of the formation of osteoclasts induced by RANKL; meanwhile, downregulating the expressions of the osteoclast cytoskeleton key signal molecules integrin αvβ3, focal adhesion kinase (FAK), c-Src, and spleen-associated tyrosine kinase (SYK). In addition, Onc201 had a protective effect on the mouse model of bone loss caused by ovariectomy-induced estrogen deficiency, which is consistent with the in vitro results. Our findings suggest that the new small-molecular compound Onc201 has the potential to prevent osteoclast-related osteolytic diseases.

HPLC-ESI-HRMS2 Determination of N-(2-Hydroxyethyl)-l-valyl-l-leucine in Human Urine: Method Validation.

Biomonitoring of human exposure to reactive electrophilic chemicals such as ethylene oxide (EO) has been commonly based on the determination of adducts with N-terminal valine in blood protein globin, but a systematic search has also been undertaken to find surrogate markers enabling non-invasive sampling. Recently, N-(2-hydroxyethyl)-L-valyl-L-leucine (HEVL) has been identified as an ultimate cleavage product of EO-adducted globin in the urine of occupationally exposed workers. Herein, full validation of the analytical procedure consisting of solid-phase extraction of HEVL from urine samples (2 mL) followed by high-performance liquid chromatography-electrospray ionization-high-resolution mass spectrometry determination using deuterium-labeled HEVL as an internal standard (IS) is described. Method limit of quantitation is 0.25 ng/mL, and its selectivity is excellent as demonstrated by the invariable ratio of the qualifier and quantifier ion intensities across diverse urine samples and synthetic standard. The linear calibration model was applicable over the whole concentration range tested (0.25-10 ng/mL). The method accuracy assessed as a recovery of HEVL using a spiking experiment was 98-100%. Within-day precision of the method ranged from 1.8% to 3.0%, while the results from consecutive analytical runs conducted within 1 week or within 10-150 weeks differed in the range of 2.2-9.7%. The stability study on urine samples (-20°C up to 3 years, freeze-and-thaw up to 10 cycles) as well as on aqueous solutions (5°C up to 4 months) indicated no relevant changes in HEVL concentration (≤4%) over the time tested. Analytical responses of both HEVL and IS correlated with urinary creatinine as an index of matrix composition, but this matrix effect was mostly eliminated using the HEVL/IS peak area ratio, attaining the IS-normalized relative matrix effect <3%. In conclusion, the method complied successfully with the bioanalytical method validation criteria, making it a reliable tool for HEVL determination in human biomonitoring.

Effect of cathode shape on the lifetime of arc discharge negative Penning ion source

Internal Penning ion source for the production of negative hydrogen ions is commonly used in various compact cyclotrons. The ion source generally operates at high power DC discharge to provide a high negative hydrogen ion beam current. In this case, the cathode will undergo intense ion sputtering and evaporation due to fierce ion collision. Then, the sputtered material from the cathode will deposit on the inner wall of the ion source discharge chamber. These deposits may lead to slight changes in the structure of the discharge chamber and affect the ion beam extraction stability. Additionally, these deposits would accidentally break and spall, inducing sudden changes in the electric field distribution or even short circuits of the discharge. As a result, the working life of the ion source is dramatically declined. Thus, the relationship between the cathode size and the plasma state was theoretically explored in this study to prolong the ion source’s lifetime. The theory suggests that the impact power of ions on the cathode can be significantly reduced when the cooling capacity of the cathode is reduced. Meanwhile, the cathode temperature is slightly increased, and the discharge voltage declines. Experiments of 4.8 mm and 6 mm in diameter of the cathode were conducted by changing the diameter of the cathode to influence the radiation cooling efficiency. Specifically, the beam current difference was within ±15% before and after changing the cathode size in the same discharge current when the small cathode was used; the beam current of the small cathode was more than 10% (even 40%) better than that of the big one at the same operating power. Before the ion source short-circuited at the same discharge current, the small and big cathode groups operated 5536 μAh and 3000 μAh, respectively. Another test demonstrated that after working for 50 h at 1.8 A discharge current, the mass loss of small cathode was 0.0456 g, and the mass loss of big cathode was 0.0798 g.

High Performance 18 GHz ECR Ion Sources Development

At present, ECR ion sources are developing towards higher frequency, higher magnetic field technology. However, 18 GHz is the highest optimal operation microwave frequency for room temperature ECR ion sources, which can meet the needs of most of the existing heavy ion facilities. After the success of the 18 GHz ECR ion source LECR4, we developed the upgraded version source LECR5 aiming for higher beam intensity and higher charge state ions. With a higher radial field, bigger plasma chamber volume, longer mirror length, and flexible Bmm field, promising results have been made at the power level of ∼2.1 kW@18 GHz, for instance, 81 eμA Bi32+, and 22 eμA Bi41+. This ion source has been recently used for the heavy ion facility SESRI (Space Environment Simulation Research Infrastructure) as the pre-injector ion source. High beam intensities and reasonable beam qualities have been demonstrated during the test platform. Inspired by this outcome, a hybrid 18 GHz ion source called HECRAL has been proposed aiming for the similar performance of SECRAL at 18 GHz. This paper will present the recent update of the LECR5 ion source commissioning. The design and preliminary results of the HECRAL ion source will be described.

Proceedings of the 19th International Conference on Ion Sources, Vancouver, BC, Canada, 2021

The 19th International Conference on Ion Sources was hosted by TRIUMF in Vancouver, BC, Canada, September 20 to September 24, 2021.The biennial conference series covers the physics and technology of ion sources for scientific research and applications. With the conference being the main event within the ion sources community, it offers a forum for the exchange of ideas and the establishing of collaborations. New developments and advancements have been presented and discussed. As in previous conferences of this series, all aspects of ion sources have been covered in the categories• Fundamental processes in ion sources and plasmas• Production of high intensity ion beams• Production of highly charged ion beams• Negative ion sources• Ion sources for fusion• Radioactive ion sources, charge breeders and polarized beams• Beam formation, extraction, transport, and diagnostics• Applications of ion sources• Key technologies for ion sourcesDue to restrictions on traveling and meeting sizes caused by health regulations during the COVID-19 pandemic, the conference was held as a virtual conference. Talks have been presented via ZOOM and two poster sessions were held within the remote meeting platform “Gather town”, which was also open for discussions among participants outside the plenary sessions.The main session on electron beam ion sources was dedicated to the memory of Professor Dr. Evgeny Denisovich Donets who, to our great regret, passed away in June 2021. Professor Donets was the inventor of the electron beam ion source and one of the initiators of this conference series. He was a longtime member of the international advisory committee. His memory will be highly regarded within the ion source community.List of International advisory committee, Scientific program committee, Local organizing committee are available in this pdf.

Space Charge Compensation Study of High Intensity Ion Beams

The space charge effect is one of the key factors affecting ion beam transport and ion beam quality, especially for low-energy high-intensity ion beams. It can be partially compensated by the secondary electrons produced from the ionization of residual gas molecules in the beam pipe, and we are interested in the accurate value of this compensation degree. In this paper, we use a Three-grid Energy Analyzer (TEA) to measure the secondary ion energy distribution of the beam, which corresponds to the compensated beam potential distribution. To have accurate evaluation of the compensation degree, it is essential to adopt a proper transverse distribution of the ion beam, other than using the Gaussian theorem for uniform beams. The results of a space charge compensation degree study for singly charged ion beams with a 2.45GHz microwave ion source and for multiply charged ion beams with a high charge state ECR ion source are presented.

Status and prospects of the 60 GHz SEISM ion source

SEISM is a unique ECR ion source operating at a frequency of 60 GHz. The prototype is based on a simple magnetic geometry, the cusp, allowing the use of polyhelix coils (developed with LNCMI, Grenoble) to generate the closed ECR surface at 2.14T. The plasma is sustained by a high intensity HF pulse (up to 300kW). Previous experiments at LNCMI have successfully demonstrated the establishment of the nominal magnetic field and the extraction of ion beams with a current density up to 1 A cm-2. The presence of afterglow peaks was also observed, proving the existence of ion confinement in a CUSP ECR source. An experimental campaign is carried out in 2021 using a new transport line designed to improve the transmission of the beam to the new detectors. Short and long-term research plans are presented to transform this high current density into a high intensity ion beam that can be used for accelerators of the future.

Voyager's observations in the vicinity of the heliopause

This work analyzes Voyager 2 observations on November 2018 and compares them with Voyager 1 data at the vicinity of the heliopause in July-August 2012. We describe the plasma and cosmic-ray variations at the radial distance of $\approx$ 1 astronomical unit (AU) from the heliopause. We use a simple convection-diffusion cosmic-ray modulation model to qualitatively explain the particle observations. We found a thin layer, with a thickness of $\approx$ 0.04 AU where the radial component of the solar wind speed vanished, the galactic cosmic ray intensity rapidly increased to reach its heliosphere boundary level, and low-energy heliospheric ion intensity drooped. We called this layer the "skin of the heliosphere". Plasma data suggest that Voyager 2 crossed the heliopause on November 5, 2018, at the radial distance of 119.03 AU. We apply our analysis to Voyager 1 observations and conclude that similar behavior in solar wind speed could qualitatively explain the GCR counting rate and that the "skin of the heliosphere" maybe a global characteristic along the heliopause.

Label-Free but Still Constrained: Assessment of Global Proteomic Strategies for the Quantification of Hepatic Enzymes and Transporters.

Building and refining pharmacology models require "system" data derived from tissues and in vitro systems analyzed by quantitative proteomics. Label-free global proteomics offers a wide scope of analysis, allowing simultaneous quantification of thousands of proteins per sample. The data generated from such analysis offer comprehensive protein expression profiles that can address existing gaps in models. In this study, we assessed the performance of three widely used label-free proteomic methods, "high N" ion intensity approach (HiN), intensity-based absolute quantification (iBAQ) and total protein approach (TPA), in relation to the quantification of enzymes and transporters in 27 human liver microsomal samples. Global correlations between the three methods were highly significant (R2 > 0.70, P < 0.001, n = 2232 proteins). Absolute abundances of 57 pharmacokinetic targets measured by standard-based label-free methods (HiN and iBAQ) showed good agreement, whereas the TPA overestimated abundances by two- to threefold. Relative abundance distribution of enzymes was similar for the three methods, while differences were observed with TPA in the case of transporters. Variability (CV) was similar across methods, with consistent between-sample relative quantification. The back-calculated amount of protein in the samples based on each method was compared with the nominal protein amount analyzed in the proteomic workflow, revealing overall agreement with data from the HiN method with bovine serum albumin as standard. The findings herein present a critique of label-free proteomic data relevant to pharmacokinetics and evaluate the possibility of retrospective analysis of historic datasets. SIGNIFICANCE STATEMENT: This study provides useful insights for using label-free methods to generate abundance data applicable for populating pharmacokinetic models. The data demonstrated overall correlation between intensity-based label-free proteomic methods (HiN, iBAQ and TPA), whereas iBAQ and TPA overestimated the total amount of protein in the samples. The extent of overestimation can provide a means of normalization to support absolute quantification. Importantly, between-sample relative quantification was consistent (similar variability) across methods.

GC–MS and GC–IR of regioisomeric 4-N-bromodimethoxybenzyl derivatives of 3-trifluoromethylphenylpiperazine

The seven regioisomeric N-bromodimethoxybenzyl derivatives of 3-TFMPP were synthesized via reductive amination of the seven commercially available bromodimethoxybenzaldehydes. The capillary GC elution profiles for these compounds generally follow the degree of methoxy group substituent crowding on the aromatic ring. The electron ionization mass spectra show a series of major fragment ions common to all seven regioisomeric compounds. The base peak in the EI mass spectra for many of the seven regioisomers occurs at m/z 229 and is the result of contributions from two isobaric fragments, the trifluoromethylphenylpiperazine cation as well as the 79Br bromodimethoxybenzyl cation. Several low intensity ions are related to the specific regioisomeric substitution patterns for the bromodimethoxybenzyl moieties and provide some differentiation for this set of seven compounds. These unique ions allow the seven compounds to be divided into sub-groups and in some cases allow specific isomer identification from only the EI-MS data. The 950 cm−1 to 550 cm−1 lower portion of the fingerprint region in the vapor phase infrared spectra can be used to identify each of the bromodimethoxybenzyl regioisomers after EI-MS fragmentation patterns provide focus on the individual structural sub-groups of compounds in this study.

Paper spray-atmospheric pressure photoionization-high resolution mass spectrometry for the direct analysis of neutral fluorinated compounds in waterproof impregnation sprays

In this work, paper spray (PS) is combined with atmospheric pressure photoionization-mass spectrometry (PS-APPI-MS) for the determination of non-polar and low polar compounds, such as the neutral per- and polyfluorinated alkyl substances (PFAS). The proposed PS-APPI-MS method has been developed for the analysis of fluorotelomer alcohols (FTOHs), fluoroctanesulfonamides (FOSAs) and fluorooctane sulfonamido-ethanols (FOSEs), using both negative ion mode and high-resolution mass spectrometry (HRMS). The most critical working parameters (i.e., UV-krypton lamp position, sample drying time, spray dopant solvent and spray voltage) have been evaluated to study both the ionization behaviour and ionization efficiency. The best results were achieved using dopant-assisted PS-APPI-HRMS with toluene as dopant solvent. The most intense ions observed in the mass spectra, [M‒H]‒ for FOSAs and [M+O2]‒• for FTOHs and FOSEs, were selected and proposed for fast screening and quantitative analysis of target compounds in waterproof impregnation sprays samples using internal standard calibration method and being able to detect down to μg L−1 levels. The satisfactory values of the method quality parameters (detection capability, repeatability, trueness and linearity) demonstrated the good performance of the PS-APPI-HRMS method and allowed the identification and quantitation of some FTOHs (6:2 FTOH, 7-Me-6:2 FTOH, 8:2 FTOH, 10:2 FTOH) and N-MeFOSE at mg L−1 in some of the waterproof impregnation spray products analyzed. This low-cost PS-APPI-HRMS method allows a fast screening, with minimum sample preparation, of non-polar and low polar compounds simultaneously, which can significantly improve the throughput on routine laboratories.

Minimizing emittance growth via low emittance transfer

The longitudinal-transverse coupling is an important source for space-charge-induced emittance growth in high intensity proton and ion linacs. Different from the equipartitioning method which tries to avoid the longitudinal-transverse coupling, a new design approach has been developed to minimize emittance growth via the low emittance transfer enabled by holding the ratio of longitudinal emittance to transverse emittance in the range of 0.9--1.4. Using a high intensity radio-frequency quadrupole accelerator as an example, a comparison between the new approach and the equipartitioning method has been made. Furthermore, input beams with non-nominal beam intensities and emittances have been applied to the designed accelerator. The simulation results show that the design obtained by following the new approach has a large tolerance for the off-design situations.

Prior Signal Acquisition Software Versions for Orbitrap Underestimate Low Isobaric Mass Tag Intensities, Without Detriment to Differential Abundance Experiments.

Tandem mass tags (TMTs) enable simple and accurate quantitative proteomics for multiplexed samples by relative quantification of tag reporter ions. Orbitrap quantification of reporter ions has been associated with a characteristic notch region in intensity distribution, within which few reporter intensities are recorded. This has been resolved in version 3 of the instrument acquisition software Tune. However, 47% of Orbitrap Fusion, Lumos, or Eclipse submissions to PRIDE were generated using prior software versions. To quantify the impact of the notch on existing quantitative proteomics data, we generated a mixed species benchmark and acquired quantitative data using Tune versions 2 and 3. Intensities below the notch are predominantly underestimated with Tune version 2, leading to overestimation of the true differences in intensities between samples. However, when summarizing reporter ion intensities to higher-level features, such as peptides and proteins, few features are significantly affected. Targeted removal of spectra with reporter ion intensities below the notch is not beneficial for differential peptide or protein testing. Overall, we find that the systematic quantification bias associated with the notch is not detrimental for a typical proteomics experiment.

Surface chemistry of atmospheric nanoparticles during a haze episode in Beijing by TOF-SIMS

The atmospheric aerosol particles have a potential heavy burden on environment, climate, and human health, which were closely related to the surface physicochemical properties. Time-of-flight secondary ion mass spectrometry (TOF-SIMS) technique is a powerful tool to obtain detailed surface chemical information since it has high surface sensitivity for both elements and molecular ions, and high mass resolution. In this work, size-fractioned aerosol particles in the range of 0.43–10 µm during a severe haze episode in Beijing were analyzed by TOF-SIMS, the variation characteristics of chemical species corresponding to particle size and air pollution level was investigated by the normalization of secondary ion intensities, the possible sources were identified through principal component analysis (PCA), and the influence of meteorological factors and air mass transmission were also investigated. The study results showed that the surface chemical components of PM2.5 were more complicated during haze episode than on clean days. A total of 17 organic and inorganic species were detected, including crustal elements, heavy metals, sulfate, nitrate, siliceous compounds, hydrocarbons, oxygen-containing organics, and nitrogen-containing organics. In general, the particle surface mainly contained crustal elements, hydrocarbons, and carbon-containing inorganics. Organic and secondary ions significantly increased in heavy-polluted days, indicating the aging process of particles. Inorganic compounds had a higher percentage in coarse mode, while organic compounds were higher in accumulation mode. PCA results indicated that urban aerosol during this haze episode mainly came from vehicle emissions (24.7%), coal-fired combustion (22.4%), organic aerosol (19.3%), and dust resuspension (19.6%). The northern air mass could facilitate the dilution of air pollutants with the surface secondary formed components of particles significantly decreased.

Specific and sensitive GC–MS analysis of hypusine, Nε-(4-amino-2-hydroxybutyl)lysine, a biomarker of hypusinated eukaryotic initiation factor eIF5A, and its application to the bi-ethnic ASOS study

Hypusination is a unique two-step enzymatic post-translational modification of the Nε-amino group of lysine-50 of the eukaryotic initiation factor 5A (eIF5A). We developed a specific and sensitive gas chromatography–mass spectrometry (GC–MS) method for the measurement of biological hypusine (Hyp), i.e., Nε-(4-amino-2-hydroxybutyl)lysine. The method includes a two-step derivatization of Hyp: first esterification with 2 M HCl in CH3OH (60 min, 80 °C) to the methyl ester (Me) and then acylation with penta-fluoro-propionic (PFP) anhydride in ethyl acetate (30 min, 65 °C). Esterification with 2 M HCl in CD3OD was used to prepare the internal standard. The major derivatization product was identified as the un-labelled (d0Me) and the deuterium-labelled methyl esters (d3Me) derivatives: d0Me-Hyp-(PFP)5 and d3Me-Hyp-(PFP)5, respectively. Negative-ion chemical ionization generated the most intense ions with m/z 811 for d0Me-Hyp-(PFP)5 and m/z 814 for the internal standard d3Me-Hyp-(PFP)5. Selected-ion monitoring of m/z 811 and m/z 814 was used in quantitative analyses. Free Hyp was found in spot urine samples (10 µL) of two healthy subjects at 0.60 µM (0.29 µmol Hyp/mmol creatinine) in the female and 1.80 µM (0.19 µmol Hyp/mmol creatinine) in the male subject. The mean accuracy of the method in these urine samples spiked with 1–5 µM Hyp was 91–94%. The limit of detection (LOD) of the method is 1.4 fmol Hyp. The method was applied to measure the urinary excretion rates of Hyp in healthy black (n = 38, age 7.8 ± 0.7 years) and white (n = 41, age 7.7 ± 1.0 years) boys of the Arterial Stiffness in Offspring Study (ASOS). The Hyp concentrations were 3.55 [2.68–5.31] µM (range 0.54–9.84 µM) in the black boys and 3.87 [2.95–5.06] µM (range 1.0–11.7 µM) in the white boys (P = 0.64). The creatinine-corrected excretion rates were 0.25 [0.20–0.29] µmol/mmol (range 0.11–0.36 µmol/mmol) in the black boys and 0.26 [0.21–0.30] µmol/mmol (range 0.10–0.45 µmol/mmol) in the white boys (P = 0.82). These results suggest that there is no ethnic-related difference in the ASOS population in the eIF5A modification. Remarkable differences were found between black and white boys with respect to correlations of urinary Hyp with amino acids and advanced glycation end-products of Lys, Arg and Cys. Deoxyhypusine, formally the direct precursor of Hyp, seems not to be excreted in the urine by healthy subjects.

Phosphoproteome Profiling Using an Isobaric Carrier without the Need for Phosphoenrichment.

Phosphorylation is a crucial component of cellular signaling cascades. It controls a variety of biological cellular functions, including cell growth and apoptosis. Owing to the low stoichiometry of phosphorylated proteins, the enrichment of phosphopeptides prior to LC-MS/MS is necessary for comprehensive phosphoproteome analysis, and quantitative phosphoproteomic workflows are typically limited by the amount of sample required. To address this issue, we developed an easy-to-establish, widely applicable, and reproducible strategy to increase phosphoproteomic signals from a small amount of sample without a phosphoenrichment step. By exploiting the multiplexing nature of isobaric labeling to generate a merged signal from multiple samples, and using a larger amount of enriched phosphopeptides as a carrier, we were able to increase trace amounts of phosphopeptides in the unpurified sample to an identifiable level and perform quantification using the reporter ion intensity of the isobaric tag. Our results showed that >1400 phosphopeptides were quantified from 250 ng of tryptic peptides prepared from cells. In a proof-of-concept of our strategy, we distinguished three types of lung cancer cell lines based on their quantitative phosphoproteomic data and identified changes in the phosphoproteome induced by drug treatment.

High Kinetic Energy Ion Mobility Spectrometry – Mass Spectrometry investigations of four inhalation anaesthetics: isoflurane, enflurane, sevoflurane and desflurane

Here we report the first High Kinetic Energy-Ion Mobility Spectrometry-Mass Spectrometric (HiKE-IMS-MS) investigations involving four fluranes; isoflurane, enflurane, sevoflurane and desflurane. Unlike standard (atmospheric pressure) IMS, HiKE-IMS can detect these compounds in positive ion mode. This is because its low-pressure environment (∼ 14 mbar) and the associated short ion drift times in the HiKE-IMS ensure the reagent ions O2+• and H3O+ are present in the reaction region, and these can react with the fluranes by dissociative charge and proton transfer, respectively. However, their ion intensities are very dependent on the value of the reduced electric field (E/N) applied and the humidity of the air in the reaction region of the HiKE-IMS. In this paper we explore the potential use of HiKE-IMS for air quality control and breath analysis of fluranes. To help in the interpretation of the ion mobility spectra, and hence the ion-flurane chemistry occurring in reaction region, a HiKE-IMS was coupled to a Time-of-Flight Mass Spectrometer so that the m/z values of both the reagent and product ions that are contained within the various ion mobility peaks observed could be identified with a high level of confidence. The dependencies of the intensities of these ions as functions of E/N (30–115 Td) and humidity in the reaction region are reported. A number of product ions have been observed only under low humidity conditions (H2O volume-mixing ratio ∼ 100 ppmv), including CHF2+ and CHFCl + for isoflurane and enflurane, CHF2+, CF3+ and C3H2F5O+ for desflurane, and CH3O+, CHF2+, C3H3F4O+, C4H3F6O+ and C4H3F6O+(H2O) for sevoflurane. It is interesting to note that CH3O+, CHF2+, CHFCl+ and CF3+ have shorter drift times than that measured for O2+•. This is explained by resonant charge transfer reaction processes occurring in the drift region: O2+• + O2 ⇌ O2+•.O2 ⇌ O2 + O2+•.

Completion of JT-60SA construction and contribution to ITER

Construction of the JT-60SA tokamak was completed on schedule in March 2020. Manufacture and assembly of all the main tokamak components satisfied technical requirements, including dimensional accuracy and functional performances. Development of the plasma heating systems and diagnostics have also progressed, including the demonstration of the favourable electron cyclotron range of frequency (ECRF) transmission at multiple frequencies and the achievement of long sustainment of a high-energy intense negative ion beam. Development of all the tokamak operation control systems has been completed, together with an improved plasma equilibrium control scheme suitable for superconducting tokamaks including ITER. For preparation of the tokamak operation, plasma discharge scenarios have been established using this advanced equilibrium controller. Individual commissioning of the cryogenic system and the power supply system confirmed that these systems satisfy design requirements including operational schemes contributing directly to ITER, such as active control of heat load fluctuation of the cryoplant, which is essential for dynamic operation in superconducting tokamaks. The integrated commissioning (IC) is started by vacuum pumping of the vacuum vessel and cryostat, and then moved to cool-down of the tokamak and coil excitation tests. Transition to the super-conducting state was confirmed for all the TF, EF and CS coils. The TF coil current successfully reached 25.7 kA, which is the nominal operating current of the TF coil. For this nominal toroidal field of 2.25 T, ECRF was applied and an ECRF plasma was created. The IC was, however, suspended by an incident of over current of one of the superconducting equilibrium field coil and He leakage caused by insufficient voltage holding capability at a terminal joint of the coil. The unique importance of JT-60SA for H-mode and high-β steady-state plasma research has been confirmed using advanced integrated modellings. These experiences of assembly, IC and plasma operation of JT-60SA contribute to ITER risk mitigation and efficient implementation of ITER operation.

Energy Spectra vs. Element Abundances in Solar Energetic Particles and the Roles of Magnetic Reconnection and Shock Acceleration

We reexamine the relationship between energy spectral indices and element abundance enhancements in solar energetic particle (SEP) events at energies of a few MeV amu−1. We find a correlated behavior only in the largest gradual SEP4 events when all ions are accelerated from the ambient coronal plasma by shock waves driven by fast, wide coronal mass ejections (CMEs). This correlated abundance behavior can track complex time variations in the spectral indices during an event. In other (SEP3) events, CME-driven shock waves, days apart, sample seed particles from a single pool of suprathermal impulsive ions contributed earlier. Of the smaller, Fe-rich, impulsive SEP events, previously related to magnetic reconnection in solar jets, over half are subsequently reaccelerated by CME-driven shock waves (SEP2), causing typical ion intensities to have a 64% correlation with shock speeds. In these SEP2 events, the onset of shock acceleration is signaled by a new component in the abundances, large proton excesses. The remaining SEP1 events lack evidence of shock acceleration. However, for all these events (SEP1–SEP3) with abundances determined by magnetic reconnection, energy spectra and abundances are decoupled.