Low-energy electron beam generation in inductively coupled plasma via a DC biased grid

Low-energy electron beam generation using a DC biased grid was investigated in an inductively coupled plasma (ICP). The electron beam was measured in argon gas at various pressures, ICP source powers, and substrate voltages (Vsub). At a low ICP source power (50 W), an electron beam was generated even at small values of Vsub (10 V), however at a high ICP source power (200 W), an electron beam was only generated when a higher voltage (30 V) was applied due to the short sheath thickness on the grid surface. The sheath on the grid surface is an important factor for generating electron beams because low-energy electrons are blocked. If the sheath thickness to small, a high voltage should be applied to generate an electron beam, as accelerate regions cannot exist without the sheath. At high pressure, since electrons experience numerous neutral collisions, a high substrate voltage is needed to generate an electron beam. However, if the applied substrate voltage becomes too high (40 V) at high pressure, high-energy electrons result in secondary plasma under the grid. Therefore, maintaining a low pressure and low ICP source power is important for generating electron beams.

The Thickness of the facial Nerve Sheath Consistently Varies by Region in Its Intra-Tympanic Course on Cadaveric Study

Objectives: Iatrogenic removal of intra-temporal disease processes, such as cholesteatoma and keratosis obturans, can be challenging when the facial nerve (FN) is involved. Despite this concern about possible FN injury during these procedures, our clinical observation has been that the diseased growth can be cleaned quite easily from the vertical FN epineurium. Therefore, we designed a cadaveric protocol to measure thickness of the FN sheath (epineurium) in horizontal, second genu and vertical FN segments and to correlate these measurements with surgical management of FN disorders. Methods: Fifty non-fixated (wet) cadaveric temporal bones were dissected over 1 year’s time. The intra-temporal FN sheath epineurium was harvested from the mid-horizontal, second genu, and mid-vertical segments. Using a digital micrometric technique, the thickness of each sample was measured. Data analysis was performed using student’s two-tailed, dependent t-test. Results: Epineurial nerve sheath thickness was the least in the horizontal segment (mean 0.9 mm, range 0.040-0.140 mm), greater at the second genu (mean 0.19 mm, range 0.010-0.280 mm), and greatest in the vertical segment (mean 0.29 mm, range 0.170-0.570 mm). These differences were statistically significant. Conclusion: In cases of cholesteatoma and keratosis obturans involving the vertical FN, the disease process can be separated from the FN sheath because of the sheath thickness in this region. Disease in the horizontal segment involves a thinner sheath and separating the disease process from the nerve is more difficult in this area.

Research on Defect Detection Technology of Composite Insulator Sheath

The composite insulator sheath plays an important role in protecting the core rod and insulation. The thickness of the sheath must meet the corresponding standard requirements. During the insulator manufacturing process, the core rod decentration leads to uneven thickness of the sheath, which is easy to cause the risk of composite insulators premature failure during operation. The phased array detection technology can accurately detect the thickness of the sheath, so that defects such as uneven thickness of the sheath (decentration of the core rod) can be detected, and the thickness of the sheath at the end of the composite insulator can also be effectively detected. DR detection technology can effectively identify the interface between the mandrel and the sheath, but there is a risk of the sheath thickness distortion due to inappropriate transillumination parameters.

RPC-MIP observations at comet 67P/Churyumov-Gerasimenko explained by a model including a sheath and two populations of electrons

The response of the mutual impedance probe RPC-MIP on board Rosetta orbiter electrostatically modeled considering an unmagnetized and collisionless plasma with two Maxwellian electron populations. A vacuum sheath surrounding the probe was considered in our model in order to take the ion sheath into account that is located around the probe, which is immersed in the cometary plasma. For the first time, the simulated results are consistent with the data collected around comet 67P/Churyumov-Gerasimenko (67P), but strong discrepancies were identified with the previous simulations that neglected the plasma sheath around the probe. We studied the influence of the sheath thickness and of the electron populations. This work helps to better understand the initially unexpected responses of the mutual impedance probe that were acquired during the Rosetta mission. It suggests that two electron populations exist in the cometary plasma of 67P.

TrkB Agonist LM22A-4 Increases Oligodendroglial Populations During Myelin Repair in the Brain

The neurotrophin, brain-derived neurotrophic factor (BDNF) promotes central nervous system (CNS) myelination during development and after injury. This is achieved via activation of oligodendrocyte-expressed tropomyosin-related kinase (Trk) B receptors. However, while administration of BDNF has shown beneficial effects, BDNF itself has a poor pharmacokinetic profile. Here, we compare two TrkB-targeted BDNF-mimetics, the structural-mimetic, tricyclic dimeric peptide-6 (TDP6) and the non-peptide small molecule TrkB agonist LM22A-4 in the cuprizone model of central demyelination in female mice. Both mimetics promoted remyelination, increasing myelin sheath thickness and oligodendrocyte densities after one-week recovery. Importantly, LM22A-4 exerts these effects in an oligodendroglial TrkB-dependent manner. However, analysis of TrkB signaling by LM22A-4 suggests rather than direct activation of TrkB, LM22A-4 exerts its effects via indirect transactivation of Trk receptors. Overall, these studies support the therapeutic strategy to selectively targeting TrkB activation to promote remyelination in the brain.