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2025
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The plasma flow generated by turbulent nonlinear interaction can improve plasma confinement by suppressing turbulence and its driven transport. Turbulence can be driven by local gradients and propagate radially from far beyond its associated correlation length. Effects of electron cyclotron resonance heating (ECRH) modulation on edge turbulence driving and spreading are first presented in the edge plasma of the HL-2A tokamak. These experiments were performed by a fast reciprocating Langmuir probe array. When ECRH modulation is applied, both the edge temperature and density are higher, and the radial electric field is stronger. The edge radial electric field, turbulence, and Reynolds stresses are all enhanced with the ECRH while the ion-ion collision rate is reduced. Figures 1 (a)-(g) present the conditional averages of the ECRH power, turbulence intensity, turbulent Reynolds stress gradient, Er×B poloidal velocity, density gradient, turbulence drive rate and turbulence spreading rate, respectively. With ECRH, both the turbulence intensity and Reynolds stress gradients increase. The maximum turbulence intensity appears at the start of the ECRH switch-off while the maximum stress gradient occurs at the end of the ECRH. The evolution of the Er×B poloidal velocity is very similar to that of the Reynolds stress gradients. This observation suggests that the poloidal flow is the result of the combined effect of turbulence nonlinear driving and damping. The enhancement of Reynolds stress during ECRH modulation mainly depends on the increase in the turbulence intensity, with the increase in radial velocity fluctuation intensity being more significant. The turbulence drive and spreading rates also increase with ECRH. The maximum drive rate appears at the start of the ECRH swithch-off while the maximum spreading rate occurs at the end of the ECRH. This analysis indicates that turbulence driving and spreading are enhanced with the former being dominant. This result suggests that the enhancements of turbulence driving and spreading lead to the enhancements of the turbulence and Reynolds stress, and thus stronger edge flows.- Book : 74(5)
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2025
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2025
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In order to extract hesperidin from Citrus aurantium L. through green and efficient ways, a novel method based on deep eutectic solvent (DES) assisted extraction has been developed. Compared to known alkali extraction and acid precipitation or organic solvent (ethanol, methanol) extraction, this new DES system of choline chloride/diethanolamine (DES-14) method exhibited excellent extraction efficiency for hesperidin. Under optimal conditions, the extraction yield of hesperidin reached 6.26 ± 0.05%. Further studies with infrared spectroscopy, 1 H nuclear magnetic resonance, and density functional theory showed the DES-14 was formed mainly through the interaction of H-bond and van der Waals forces. In addition, scanning electron microscopy and density functional theory revealed the strong dissolving capacity, and the H-bond formation between DES-14 and hesperidin, as well as van der Waals forces all contributed to efficient extraction of hesperidin. The results provide a new strategy for efficient extraction and utilization of hesperidin in Citrus.- Book : ()
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2025
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2025
T. H. Rider investigated the challenges of sustaining p-11B fusion away from ThermoNuclear Steady-State accounting for Bremsstrahlung losses (TNSSB) in his 1997 paper [Phys. Plasmas 4, 1039 (1997)]. We revisit part of his work using first-principles particle simulations, which more accurately capture the underlying physical processes. This study supports the aspects of Rider's analysis by considering non-Maxwellian electron velocity distributions and significantly lowering electron temperatures compared to ion temperatures. Under these conditions, the minimum recirculating power needed to sustain a non-TNSSB state remains much higher than the fusion power output. However, by using updated fusion cross section data and expanding Rider's parameter space to include higher electron temperatures, we find a net energy gain window. This is consistent with findings by Putvinski et al. [Nucl. Fusion 59, 076018 (2019)]. Higher electron temperatures increase Bremsstrahlung radiation losses but reduce electron-ion energy transfer. For non-TNSSB p-11B fusion plasmas, as the system approaches a TNSSB state, achieving net energy gain requires lower energy conversion efficiencies. Near ignition conditions (Qfuel≥10) are found when ion temperatures (Ti) range from 200 to 600 keV in a TNSSB. At these conditions, an optimal electron-to-ion temperature ratio (Te/Ti) between 0.4 and 0.6 minimizes the required product of plasma density and confinement time, provided Bremsstrahlung losses are offset by electron-ion interaction power. Reducing Te/Ti below this range for a given Ti increases the required recirculating power and reduces the achievable Q. Finally, deviations from Maxwellian velocity distributions for electrons and ions may offer additional pathways toward achieving ignition.- Book : 32(1)
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2025
Background A vestibular implant can partially restore vestibular function by providing motion information through implanted electrodes. During vestibular implantation, various obstructions of the semicircular canals, such as protein deposits, fibrosis, and ossification, can be encountered. The objective was to explore the relationship between preoperative imaging and intraoperative findings of semicircular canal obstruction and to develop surgical strategies for dealing with obstructions of the semicircular canal(s) in patients eligible for vestibular implantation. Methods Patients undergoing vestibulocochlear implantation (in an active clinical trial) were included in the current study when preoperative imaging indicated an obstruction in the semicircular canal. Preoperative imaging consisted of CT and MRI scans. During surgery, the bony semicircular canals were skeletonized (“bluelined”) to identify the course of the canals and create a fenestration to insert the electrodes. The aim was to place the electrodes in the semicircular canal ampullae. Surgical strategies were developed to deal with the soft tissue obstructions. These procedures were evaluated intraoperatively with microscopic visualization, postoperatively with CT imaging. Results The three included patients suffered from bilateral vestibulopathy and hearing loss due to autosomal dominant nonsyndromic sensorineural deafness 9 (DFNA9). A soft tissue obstruction was predicted in one semicircular canal (2 patients) or two semicircular canals (1 patient), based on preoperative imaging. Intraoperatively, bluelining the semicircular canals aided in identifying these locations, by revealing a “whiteline” instead of blueline. Depending on the nature and location of the obstruction, different surgical procedures were employed to facilitate proper electrode insertion. These were as follows: a dummy electrode was used to probe the soft tissue, the obstructive tissue was removed, and/or a bypass fenestration was created. In all patients, the electrodes could be implanted in the semicircular canal ampullae. Based on these first experiences, a diagnostic and surgical guide to deal with obstructions of the semicircular canals during vestibular implantation was developed. Conclusions Preoperative imaging can indicate locations of obstructions in the SCCs. Different surgical procedures can be applied to enable appropriate electrode positioning in the SCC ampulla. This article describes the first experiences with obstructions of the semicircular canals during intralabyrinthine vestibular implantation and presents a diagnostic and surgical guide. Trial registration ABR NL73492.068.20, METC20-087 (Maastricht University Medical Center) and NAC 11-080 (Geneva University Hospitals). - Book : 54()
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