A double‐mode planar argon plume produced by varying the distance from an atmospheric pressure plasma jet

Abstract Atmospheric pressure planar plumes are desirable for the applications of low temperature plasmas, such as rapid modification of large‐scale surfaces. Up to now, only single‐mode planar plumes with either a streamer mode or a filamentary mode have been reported in the literature. Distinctive from the single‐mode planar plumes, a double‐mode argon planar plume has been generated in this article, which operates in the streamer mode with a larger distance away from a plasma jet and transits to the filamentary mode with decreasing the distance. Discharge characteristics and plasma parameters are compared for the two modes. Results indicate that the streamer mode and the filamentary mode correspond to pulsed and humped discharges respectively. Fast photography reveals that the streamer‐mode plume is composed of stochastically branching streamers, while the filamentary‐mode plume results from a series of moving filaments similar to those in barrier discharge. In contrast to the streamer mode, the filamentary mode has lower excited electron temperature and vibrational temperature, whereas higher electron density and gas temperature. In addition, better hydrophilicity of polyethylene terephthalate surface is achieved in the filamentary mode

Assessment on gas‐polyethylene terephthalate solid interface partial discharge properties of C4F7N/CO2 gas mixture for eco‐friendly gas insulating transformer

Abstract The eco‐friendly insulating gas perfluoroisobutyronitrile (C4F7N) is potentially used in gas‐insulated transformers (GIT) to replace sulphur hexafluoride (SF6). However, evaluation of the long‐term insulation reliability and gas–solid interface discharge decomposition characteristics of the gas–solid film insulation structure in GIT is indispensable. The authors simulated the gas–solid film insulation structure in GIT and explored the interface partial discharge (PD) characteristics of C4F7N/CO2 gas mixture with polyethylene terephthalate (PET). The effect of gas pressure, mixing ratio on gas–solid interface gas decomposition, PET degradation was investigated, and the interaction mechanism was analysed. It is found that the interface PD generated three degradation regions on a PET film. The gas–solid interface reaction in the electrode contact region and the discharge development trace was significantly higher than that of halation region. The content of gas decomposition products decreases with the increase of gas pressure and the PD intensity of SF6‐PET is inferior to that of C4F7N/CO2 under the same condition. Relevant results provide reference for the development and application of C4F7N/CO2 based GIT

Mesenchymal stromal cells plus basiliximab improve the response of steroid-refractory acute graft-versus-host disease as a second-line therapy: a multicentre, randomized, controlled trial

Abstract Background For patients with steroid-refractory acute graft-versus-host disease (SR-aGVHD), effective second-line regimens are urgently needed. Mesenchymal stromal cells (MSCs) have been used as salvage regimens for SR-aGVHD in the past. However, clinical trials and an overall understanding of the molecular mechanisms of MSCs combined with basiliximab for SR-aGVHD are limited, especially in haploidentical haemopoietic stem cell transplantation (HID HSCT). Methods The primary endpoint of this multicentre, randomized, controlled trial was the 4-week complete response (CR) rate of SR-aGVHD. A total of 130 patients with SR-aGVHD were assigned in a 1:1 randomization schedule to the MSC group (receiving basiliximab plus MSCs) or control group (receiving basiliximab alone) (NCT04738981). Results Most enrolled patients (96.2%) received HID HSCT. The 4-week CR rate of SR-aGVHD in the MSC group was obviously better than that in the control group (83.1% vs. 55.4%, P = 0.001). However, for the overall response rates at week 4, the two groups were comparable. More patients in the control group used ≥ 6 doses of basiliximab (4.6% vs. 20%, P = 0.008). We collected blood samples from 19 consecutive patients and evaluated MSC-derived immunosuppressive cytokines, including HO1, GAL1, GAL9, TNFIA6, PGE2, PDL1, TGF-β and HGF. Compared to the levels before MSC infusion, the HO1 (P = 0.0072) and TGF-β (P = 0.0243) levels increased significantly 1 day after MSC infusion. At 7 days after MSC infusion, the levels of HO1, GAL1, TNFIA6 and TGF-β tended to increase; however, the differences were not statistically significant. Although the 52-week cumulative incidence of cGVHD in the MSC group was comparable to that in the control group, fewer patients in the MSC group developed cGVHD involving ≥3 organs (14.3% vs. 43.6%, P = 0.006). MSCs were well tolerated, no infusion-related adverse events (AEs) occurred and other AEs were also comparable between the two groups. However, patients with malignant haematological diseases in the MSC group had a higher 52-week disease-free survival rate than those in the control group (84.8% vs. 65.9%, P = 0.031). Conclusions For SR-aGVHD after allo-HSCT, especially HID HSCT, the combination of MSCs and basiliximab as the second-line therapy led to significantly better 4-week CR rates than basiliximab alone. The addition of MSCs not only did not increase toxicity but also provided a survival benefit

Additional file 1 of Mesenchymal stromal cells plus basiliximab improve the response of steroid-refractory acute graft-versus-host disease as a second-line therapy: a multicentre, randomized, controlled trial

Additional file 1. Protocol for the prevention of infections