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Physics related to fast ions in magnetically confined fusion plasmas is a very important issue, since these particles will play an important role in future burning plasmas. Indeed, they will act as primary heating source and will sustain the self-ignited condition. To measure the fast ion slowing-down times in a magnetohydrodynamic-quiescent plasmas in different scenarios, very short pulses of a deuterium neutral beam, so-called 'blip,' with duration of about 5 ms were tangentially co-injected into a deuterium plasmas at the HuanLiuqi-2A (commonly referred to as HL-2A) tokamak [L. W. Yan, Nucl. Fusion 51, 094016 (2011)]. The decay rate of 2.45 MeV D-D fusion neutrons produced by beam-plasma reactions following neutral beam termination was measured by means of a 235U fission chamber. Experimental results were compared with those predicted by a classical slowing-down model. These results show that the fast ions are well confined with a peaked profile and the ions are slowed down classically without significant loss in the HL-2A tokamak. Moreover, it has been observed that during electron cyclotron resonance heating the fast ions have a longer slowing-down time and the neutron emission rate decay time becomes longer. [ABSTRACT FROM AUTHOR]

The pellet pacing ELM mitigation concept is being tested in some tokamaks such as ASDEX Upgrade, DIII-D and JET. By increasing the ELM frequency, the ELM size can be reduced and eventually suppressed to meet the lifetime requirements on ITER target plates. In the HL-2A tokamak, ELMy H-mode operation is routinely performed and small type-III ELMs with a high repetition rate and some type-I (or possibly large type-III) ELM events are observed. Large ELMs are often preceded by strong coherent magnetic oscillations, and produce obvious perturbations on plasma current Ip, electron density ñedge at the edge, stored energy WE, etc. The coherent magnetic oscillations before an ELM crash or during the ELM are measured by toroidal and poloidal Mirnov coils and analysed by the wavelet technique to study the spectral characteristics of the short time ELM events. Pellet injection experiments are performed in type-III ELMy H-mode plasmas and ELM-free H-mode plasmas to study the physics of pellet triggering ELM. The analyses of pellet-induced ELMs and spontaneous ELMs are presented. Because the pellet size is relatively large, it induces magnetic oscillations lasting longer than that of a natural ELM. [ABSTRACT FROM AUTHOR]

In an experimental study of the runaway electron generation during major disruptions in the HuanLiuqi-2A (commonly referred to as HL-2A) [L. W. Yan, Nucl. Fusion 51, 094016 (2011)] tokamak, detailed time and space resolved x-ray images of the long-lived runaway electron beam in flight have been observed and these allow a detailed analysis of the generation and evolution of the disruption produced runaway electron beam in a major disruption, where the conversion efficiency of pre-disruption plasma current into runaway current is up to 55% on HL-2A tokamak. Moreover, a delay of about 7 ms between the start of the disruption and the formation of runaway electron beam has been found. With the aid of the Equilibrium FIT (EFIT) code, magnetic configuration reconstruction has made possible a detailed observation of the magnetic flux geometry evolution during major disruptions. The EFIT magnetic configuration reconstructions show that the delay is due to the transient strong deformation of the magnetic configuration in the initial stage of the current quench, which may provide a possibility of suppressing or mitigating the runaway electron beam during this period by massive gas injection or other methods. [ABSTRACT FROM AUTHOR]

Interactions among pedestal shear flows, turbulence, and the formation of the edge transport barrier have been studied in H-mode plasmas of the HL-2A tokamak by multi-channel Doppler reflectometry with high spatiotemporal resolution. Geodesic acoustic mode (GAM) has been observed during the L-I-H transition. It has been observed that the plasma transits into the I-phase when the mean E × B shear flow reaches a critical value. The bi-spectrum analysis has shown that there is a strong interaction between GAM and limit cycle oscillation (LCO), and the energy transfer is from GAM to LCO, suggesting that GAM can assist the L-I transition. The regulation of the edge turbulence by LCOs helps to build the steep pedestal and initialize the confinement improvement of the plasma. It has been found that the mean E × B shear flow is further increased just before the I-H transition, accompanied by the turbulence suppression, leading to the edge transport reduction and the pedestal formation. It has been demonstrated that the increase of the mean E × B shear flow prior to the L-I and I-H transitions is due to the ion diamagnetic component of E r . These results corroborate that the mean E × B shear flow plays a key role in the L-I and I-H transitions. [ABSTRACT FROM AUTHOR]

The absolute rate of nonlinear energy transfer among broadband turbulence, low-frequency zonal flows (ZFs) and geodesic acoustic modes (GAMs) was measured for the first time in fusion-grade plasmas using two independent methods across a range of heating powers. The results show that turbulent kinetic energy from intermediate frequencies (20-80 kHz) was transferred into ZFs and GAMs, as well as into fluctuations at higher frequencies (> 80 kHz). As the heating power was increased, the energy transfer from turbulence into GAMs and the GAM amplitudes increased, peaked and then decreased, while the energy transfer into the ZFs and the ZFs themselves increased monotonically with heating power. Thus there exists a competition between ZFs and GAMs for the transfer of turbulent energy, and the transfer into ZFs becomes dominant as the heating power is increased. The poloidal-radial Reynolds stress and the mean radial electric field profiles were also measured at different heating powers and found to be consistent with the energy transfer measurement. The results suggest that ZFs play an important role in the low-to-high (JL-H) plasma confinement transition [ABSTRACT FROM AUTHOR]

To explore the situation of 8 common respiratory pathogens in children with acute respiratory infection (ARI) from 2021 to 2022.The retrospective study selected 8 710 ARI patients from September 2021 to August 2022 in the Maternal and Child Health Hospital of Gansu Province as the study object, patients aged 0 to 17 years old, including 5 048 male children and 3 662 female children. Indirect immunofluorescence was used to detect 8 common respiratory pathogens, including influenza virus A (FluA), influenza virus B (FluB), parainfluenza virus (PIV), respiratory syncytial virus (RSV), adenovirus (ADV), Mycoplasma pneumoniae (MP), Chlamydia pneumoniae (CP), and Coxsackie virus group B (CoxB) IgM antibodies. χ 2 test was used to analyze the results. The results showed that 1 497 of 8 710 children with ARI were positive, with a positive rate of 17.19%. The detection rate of MP among 8 common respiratory pathogens was 11.34%, accounting for 66.0%, followed by FluB, CoxB, PIV, RSV, ADV, FluA and CP, accounting for 13.83%, 9.55%, 6.01%, 2.61%, 1.47%, 0.40% and 0.13%, respectively. Respiratory tract viruses (FluA, FluB, RSV, ADV, PIV, CoxB) accounted for 33.86%.There were significant differences in the detection rates of PIV, ADV and MP among children of different genders (χ 2 =6.814, 5.154 and 17.784, P <0.05). The detection rate of school-age children (6-17 years old) was the highest, accounting for 33.27% (184/553). The detection rates of 8 common respiratory pathogens in patients with ARI were higher in spring and winter and lower in summer and autumn. To sum up, from 2021 to 2022, MP and FluB infection were dominant in ARI patients in our hospital. The peak period of 8 common respiratory pathogens was in spring and winter. The physical examination rate of 8 common respiratory pathogens in ARI patients aged 6-17 years old was the highest.

Objective: To study the effects of miR-16-5p on proliferation, migration and invasion of osteosarcoma cells and its mechanism. Methods: Quantitative polymerase chain reaction (qPCR) and Western blotting were used to detect the mRNA and protein expression of miR-16-5p and TSPAN15 in human normal osteoblasts hFOB 1.19 and osteosarcoma cells MG63, Saos2 and HOS. The miR-16-5p or si-TSPAN15 was transfected into MG63 cells to observe its role in cell proliferation, migration and invasion. Cell proliferation was measured with MTT assay, cell migration and invasion were examined by Transwell, and the protein expression of CyclinD1, matrix metalloproteinase 2 (MMP-2), MMP-9, tetraspanin 15 (TSPAN15), phospha-tidylinositol3-kinase(p-PI3K) and phospha-protein kinase B(p-AKT) were determined by using Western blotting. The starbase website prediction combined with dual luciferase gene reporter assay was performed to analyze the targeting relationship between miR-16-5p and TSPAN15. miR-16-5p and pcDNA-TSPAN1 were co-transfected to assess the effect of high expression of TSPAN15 on overexpression of miR-16-5p-induced proliferation, migration and invasion of MG63 cells. Data comparison between the two groups was performed by using t test. Results: Compared with hFOB 1.19 cells (1.00±0.12), the expression of miR-16-5p was significantly decreased in MG63, Saos2 and HOS cells (0.32±0.05, 0.40±0.04, 0.45±0.06, respectively)( F= 156.204, P< 0.05), and TSPAN15 mRNA and protein levels were greatly increased ( F= 71.718, 110.350, both P< 0.05). Overexpression of miR-16-5p obviously reduced the expression of CyclinD1, MMP-2, MMP-9 protein, cell viability, cell migration and invasion ( F= 150.136,117.228, 154.971, 89.479, 98.373, 130.880, all P< 0.05) in MG63 cells. Knockdown of TSPAN15 greatly reduced CyclinD1, MMP-2, MMP-9 protein levels, cell survival rate, cell migration, and invasion number ( F= 93.206, 107.030, 109.326, 115.625, 146.113, 139.300, all P< 0.05). Overexpression of miR-16-5p markedly decreased the expression of p-PI3K and p-AKT protein in MG63 cells ( F= 156.755, 181.419, both P< 0.05). miR-16-5p targeted to regulate the expression of TSPAN15. High expression of TSPAN15 partially reversed the inhibitory effect of miR-16-5p on TSPAN15, CyclinD1, MMP-2, MMP-9, p-PI3K, p-AKT protein expression, cell viability, cell migration number and invasion number in MG63 cells. Conclusion: miR-16-5p inhibits the proliferation, migration and invasion of osteosarcoma cells by targeting the TSPAN15 gene and regulating the PI3K/AKT signaling pathway.

A randomised double-blind intervention trial was carried out in Huixian, Henan Province, People's Republic of China, to determine whether combined treatment with retinol, riboflavine, and zinc could lower the prevalence of precancerous lesions of the oesophagus. 610 subjects in the age group 35-64 were randomised to receive once a week the active treatment (15 mg [50 000 IU] retinol, 200 mg riboflavine, and 50 mg zinc) or placebo. Both at entry to the study and at the end of the treatment, 13.5 months later, the subjects were examined, with an emphasis on signs of vitamin A and riboflavine deficiences, and riboflavine, retinol, beta-carotene, and zinc levels were measured. Compliance was excellent. The final examination, on 567 (93%) subjects, included oesophagoscopy and at least two biopsies. The intervention did not affect the prevalence of oesophageal lesions: after one year, the prevalence of oesophagitis with or without atrophy or dysplasia was 45.3% in the placebo group and 48.9% in the vitamin/zinc treated group.