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Abstract FOXG1 syndrome is a developmental encephalopathy caused by FOXG1 (Forkhead box G1) mutations, resulting in high phenotypic variability. However, the upstream transcriptional regulation of Foxg1 expression remains unclear. This report demonstrates that both deficiency and overexpression of Men1 (protein: menin, a pathogenic gene of MEN1 syndrome known as multiple endocrine neoplasia type 1) lead to autism‐like behaviors, such as social defects, increased repetitive behaviors, and cognitive impairments. Multifaceted transcriptome analyses revealed that Foxg1 signaling is predominantly altered in Men1 deficiency mice, through its regulation of the Alpha Thalassemia/Mental Retardation Syndrome X‐Linked (Atrx) factor. Atrx recruits menin to bind to the transcriptional start region of Foxg1 and mediates the regulation of Foxg1 expression by H3K4me3 (Trimethylation of histone H3 lysine 4) modification. The deficits observed in menin deficient mice are rescued by the over‐expression of Foxg1, leading to normalized spine growth and restoration of hippocampal synaptic plasticity. These findings suggest that menin may have a putative role in the maintenance of Foxg1 expression, highlighting menin signaling as a potential therapeutic target for Foxg1‐related encephalopathy.

Numerous bacteria, fungi and other microorganisms in the tobacco phyllosphere interstellar area participate in the physiological metabolism of plants by interacting with the host. However, there is currently little research on the characteristics of tobacco phyllosphere microbial communities, and the correlation between tobacco phyllosphere microbial communities and phyllosphere factor indicators is still unknown. Therefore, high-throughput sequencing technology based on the 16S rRNA/ITS1 gene was used to explore the diversity and composition characteristics of tobacco phyllosphere bacterial and fungal communities from different maturation processes, and to identify marker genera that distinguish phyllosphere microbial communities. In this study, the correlations between tobacco phyllosphere bacterial and fungal communities and the precursors of major aroma compounds were explored. The results showed that as the tobacco plants matured, the density of glandular trichomes on the tobacco leaves gradually decreased. The surface physicochemical properties of tobacco leaves also undergo significant changes. In addition, the overall bacterial alpha diversity in the tobacco phyllosphere area increased with maturation, while the overall fungal alpha diversity decreased. The beta diversity of bacteria and fungi in the tobacco phyllosphere area also showed significant differences. Specifically, with later top pruning time, the relative abundances of Acidisoma, Ralstonia, Bradyrhizobium, Alternaria and Talaromyces gradually increased, while the relative abundances of Pseudomonas, Filobassidium, and Tausonia gradually decreased. In the bacterial community, Acidisoma, Ralstonia, Bradyrhizobium, and Alternaria were significantly positively correlated with tobacco aroma precursors, with significant negative correlations with tobacco phyllosphere trichome morphology, while Pseudomonas showed the opposite pattern; In the fungal community, Filobasidium and Tausonia were significantly negatively correlated with tobacco aroma precursors, and significantly positively correlated with tobacco phyllosphere trichome morphology, while Alternaria showed the opposite pattern. In conclusion, the microbiota (bacteria and fungi) and aroma precursors of the tobacco phyllosphere change significantly as tobacco matures. The presence of Acidisoma, Ralstonia, Bradyrhizobium and Alternaria in the phyllosphere microbiota of tobacco may be related to the aroma precursors of tobacco.

Supercritical water oxidation is a promising technology for decomposition of industrial wastewater and sludge. However, the system is operated under high temperature and pressure (usually higher than 500 °C and 25 MPa). Corrosion of component materials and salt deposition may lead to leakage or even the burst of the pressure vessel in the SCWO system, resulting in a high level of worry about the safe operation of the system. In this paper, the safety management and accident- control strategies are introduced according to a commercial-scale SCWO plant in China. The safety management strategy refers to the special design and operation strategies of some facilities. Different types of potential accidents are analyzed and the coping strategies for accidents of different levels of severity are described in detail. The strategies are valuable for the safe operation of commercial SCWO plants and other plants operated in high temperature and high pressure.

This effort is to investigate three different Cu-based oxygen carriers (OCs) with polyvinyl chloride (PVC) and coal in chemical-looping combustion (CLC). The combustion process and synergetic analysis of PVC with coal were evaluated. There were four stages in the reaction of OCs with PVC, which HCl released from PVC could react with OCs at about 200–400 °C. CuO and CuO modified by limestone showed better immobilization of chlorine while CuO modified by iron ore and chrysolite inhibited the reaction of HCl with CuO. PVC char combustion temperature started at about 500 °C which were lower than that of coal char. The combustion efficiency of PVC CLC was all above 92%, except using Cu-Fe as OC which was about 88%. The presence of ZD in PVC showed positive effect on every stage. The addition of coal inhibited the reaction of HCl with CuO. The presence of PVC in ZD reduced the temperature of coal char and the addition of ZD in PVC increased the reaction rate. The synergistic effect was obvious between the PVC and coal blends which is beneficial for the complete combustion in solid fuel CLC

To solve the problem of mode competition in high-order working modes, this paper presents a fast design method based on the TM31-2π mode for the dumbbell shaped extended interaction cavity. Based on the equivalent circuit theory, the high-frequency characteristics of the structure are studied. In addition, we propose a W-band continuous wave sheet beam extended interaction klystron high-frequency circuit. The circuit was driven by a 20 kV and 0.85 A sheet electron beam, with a 3.2 × 0.3 mm2 section. The beam was focused by a 0.8 T permanent magnet system. The high-frequency system adopts five dumbbell shaped five-gap cavities, and the output system adopts a symmetrical output waveguide. The 3D particle-in-cell simulation shows that more than 1.5 kW power can be obtained at an input power of 0.12 W, and the electron efficiency and gain are 9.2% and 41.2 dB, respectively.

LiFePO4/N-doped C composites with core–shell structures were synthesized by a convenient solvothermal method. Cetyltrimethylammonium bromide (CTAB) and glucose were used as nitrogen and carbon sources, respectively. The growth of LiFePO4 nanocrystals was regulated by CTAB, resulting in an average particle size of 143 nm for the LiFePO4/N-doped C. The N atoms existed in the carbon of LiFePO4/N-doped C in the form of pyridinic N and graphitic N. The LiFePO4/N-doped C composites delivered discharge specific capacities of 160.7 mAh·g−1 (0.1 C), 128.4 mAh·g−1 (5 C), and 115.8 mAh·g−1 (10 C). Meanwhile, no capacity attenuation was found after 100 electrochemical cycles at 1 C. N-doping enhanced the capacity performance of the LiFePO4/C cathode, while the core–shell structure enhanced the cycle performance of the cathode. The electrochemical test data showed a synergistic effect between N-doping and core–shell structure on the enhancement of the electrochemical performance of the LiFePO4/C cathode.

Abstract We attempted to explore the effect of Rho guanine nucleotide exchange factor 39 (ARHGEF39) on the phenotypes of clear cell renal cell carcinoma (ccRCC) cells and the underlying mechanism. Analyses of the data from The Cancer Genome Atlas (TCGA) illustrated that ARHGEF39 expression was upregulated in ccRCC and high ARHGEF39 expression was correlated with a worse prognosis. The mRNA and protein expression of ARHGEF39 in ccRCC and nontumorigenic cells was measured by qRT-PCR and western blotting, respectively. The results showed that ARHGEF39 expression was upregulated in ccRCC cells compared with nontumorigenic cells. CCK8 and clonogenic assays were used to measure the viability of ccRCC cells after knockdown or overexpression of ARHGEF39. Transwell assays were used to examine the changes in cell motility after alterations in ARHGEF39 expression and treatment with LY294002 (an AKT inhibitor) or PD98059 (an ERK inhibitor). ARHGEF39-mediated changes in the phosphorylation of AKT and ERK were measured by western blotting. The results indicated that ARHGEF39 promoted the viability, migration and invasion of ccRCC cells by regulating the activation of the AKT/ERK signaling pathway. Overall, our research suggested that ARHGEF39 was upregulated in ccRCC and possibly facilitated the malignant development of ccRCC by modulating the AKT/ERK signaling pathway.

Gossypol is a yellow polyphenolic compounds extracted from roots, stems and seeds of cotton plants. Excessive intake of gossypol induces severe pathological signs of toxicity in livestock and wildlife. Currently, gossypol has received widespread attention for its toxic effects on the reproductive system. However, reports of the effects of gossypol during corticogenesis and the development of the mouse cerebral cortex are unavailable. In the present study, gossypol was orally administrated at a dose of 0, 20, and 50 mg/kg body weight/day to pregnant mice from embryonic day 6.5 to the time of sample collection. We used in utero electroporation and immunofluorescence to demonstrate that gossypol impaired cortical neuronal migration. Furthermore, labeling with 5-bromo-2-deoxyuridine and western blot analysis revealed that gossypol disturbed the balance between proliferation and differentiation of neural progenitors, inhibited neural progenitor cell proliferation, neuronal differentiation, and maturation. Additionally, cortical progenitor apoptotic cell death increased in the developing gossypol-treated cortex, which was associated with NF-κB and MAPK pathways. In conclusion, our findings indicate that gossypol exposure disrupted neurogenesis in the developing neocortex, suggesting the potentially harmful impact of gossypol on the cerebral cortex development of humans and livestock.

Supercritical water oxidation (SCWO) is a promising wastewater treatment technology owing to its various advantages such as rapid reactions and non-polluting products. However, problems like corrosion and salt decomposition set obstacles to its commercialization. To address these problems, researchers have been developing the optimal reactor design and strengthening measures based on sufficient understandings of the degradation kinetics. The essence of the SCWO process and the roles of oxygen and hydrogen peroxide are summarized in this work. Then, the research status and progress of empirical models, semi-empirical models, and detailed chemical kinetic models (DCKMs) are systematically reviewed. Additionally, this paper is the first to summarize the research progress of quantum chemistry and molecular dynamics simulation. The challenge and further development of kinetics models for the optimization of reactors and the directional transformation of pollutants are pointed out.

Supercritical hydrothermal combustion, a new and promising homogeneous combustion technology with a wide range of application scenarios and broad development prospects, provides creative ideas and means for the enhanced degradation of organic wastes, hydrothermal spallation drilling, thermal recovery of heavy oil, etc. This technology is elaborated upon in five parts: (1) introducing the main devices including semi-batch reactor and continuous reactor to study the hydrothermal flame in accordance with research institutions, (2) presenting the research status of related numerical simulation from the angles of reaction kinetics and flow-reaction, (3) summarizing the characteristics of hydrothermal flame and combustion by five key parameters, (4) dividing up ignition process and explaining ignition mechanism from the perspectives of critical physical properties of water and heat transfer and mixing conditions, (5) discussing and forecasting its industrial applications including hydrothermal spallation drilling, the thermal recovery of heavy oil, the clean conversion and utilization of coal-based fuel, and the harmless treatment of pollutants. By and large, this paper analyzed in detail everything from experimental equipment to industrial applications, from combustion characteristics to ignition mechanisms, and from summary conclusions to prospect prediction. In the end, herein is summarized a couple of existing paramount scientific and technical obstacles in hydrothermal combustion. Further significant studies in the future should include excellent reactors, advanced monitoring techniques, and powerful computational fluid dynamics.

The dependencies of weight gain of 9-12 Cr ferritic-martensitic steels in supercritical water on each of seven principal independent variables (temperature, oxygen concentration, flow rate, exposure time, and key chemical composition and surface condition of steels) have been predicted using a supervised artificial neural network (ANN). The relative significance of each independent variable was uncovered by fuzzy curve analysis, which ranks temperature and exposure time as the most important. The optimized ANN, not only satisfactorily represents the experimentally-known non-linear relationships between the corrosion characteristics of F-M steels and the key independent variables (demonstrating the effectiveness of this technique), but also predicts and reveals that the effects of oxygen concentration on the weight gains, to a certain degree, is influenced by the flow rate and temperature. Finally, according to the ANN predicted-results, departure of oxidation kinetics from the parabolic law, and basic cause of chromium content in steel substrate influencing the corrosion rate, and the synergetic effects of dissolved oxygen concentration, flow rate, and temperature, are discussed and analyzed.

The corrosion behaviors of 316 stainless steel (316 SS), Inconel 600, Inconel 625, Hastelloy C-276 and TA10 coupons exposed in supercritical water (400°C/25 MPa) with sodium chloride, sodium triphosphate and hydrogen peroxide were investigated by using SEM, XRD and XPS. 316 SS shows the most severe spallation of oxide scales and Inconel 600 exhibited the most severe pitting corrosion due to a lack of molybdenum in the alloy. TA10 showed the lowest corrosion rate and the slightest corrosion morphology. TA10 had corrosion rates less than 1.8 mmpy in the four experiments and a triplex oxide layer structure formed which consisted of TiO2/Ti2O3/TiO from outer to inner layer. The formation of (TiO) 2P2O7 was observed on TA10 in oxidizing supercritical water containing phosphate. Phosphate shows significant corrosion inhibition for metal alloys in SCWO due to the formation of a passivating metal phosphate film. An oxide film growth mechanism, metal dissolution mechanism and metal salt precipitation mechanism are discussed in order to explain the corrosion behavior of the specimens in this research. [ABSTRACT FROM AUTHOR]

Supercritical hydrothermal combustion has received a great deal of attention as an innovative and potential treatment technology wherein the corrosion and salt deposition problems during supercritical water oxidation processes can be avoided effectively. A detailed chemical kinetics model for methanol was employed and validated to understand the hydrothermal combustion process mechanism in supercritical water. Based on this elementary reaction model, how the two key indicators (ignition and extinction temperatures) worked during combustion reaction was studied. Moreover, the influences of operational parameters (fuel concentration, oxidation coefficient and reactor type) and corresponding reaction mechanism were investigated. It reveals that H202 was identified as one key intermediate product in the combustion kinetics of methanol. Initial concentration and injection flow rate of aqueous fuel were two significant factors that determined the extinction temperature, which decreased as the concentration increased or the injection flow rate reduced. Moreover, a minimum limit for the initial fuel concentration existed above which a stable hydrothermal flame could form. The oxidation coefficient affected combustion temperature in a manner that depended on the coefficient range. The combustion temperature elevated with the oxidation coefficient in the fuel-rich area while dropped in the oxidant-rich area. This phenomenon was interpreted from the point of view of thermodynamics and mechanism. In order to maintain stable flames at as a low injection temperature as possible, vessel reactors were more desirable to be applied for hydrothermal combustion reaction, deriving from the discrepancy in order of magnitude for flow velocity between tubular and vessel reactors. Finally, it is found that the enhancement of auxiliary fuel methanol in decomposition of organic pollutants stemmed from two reasons: high reaction heat release and co-oxidative effect, whereas the refractory compounds could suppress the ignition of methanol in supercritical water. [ABSTRACT FROM AUTHOR]

In this work the particle size control method of copper nanoparticles synthesized in supercritical water was investigated. The experiments were respectively carried out in a flow-type reaction apparatus and in a batch-type quartz tube apparatus. Results show that particle size of the products was very sensitive to the concentration of copper sulfate and alkalinity of the reactant. When the concentration of copper sulfate increased from 0.05 mol/L to 0.5 mol/L, the average particle size increased from 14nm to 50 nm. When the molar ratio of NaOH to copper ion increased from 0:1 to 2:1, the average particle size decreased from 85 nm to 14 nm. The homogeneity and dispersity of the products were improved by increasing the concentration of complexing agent ethylenediamine tetraacetic acid (EDTA). The adsorption mechanism of EDTA on the surfaces of nanoparticles was researched by a Fourier transform infrared spectroscopy. It was speculated that EDTA adsorbed on the surfaces of nanoparticles by the dehydration reaction of carboxyl groups in the molecule of EDTA and hydroxyl groups on surfaces of copper nanoparticles (-Cu-OH). These results are expected to be of great interest as basic data for the preparation of size-controlled copper nanoparticles by supercritical hydrothermal synthesis method. [ABSTRACT FROM AUTHOR]

The flow behaviors of two-dimensional (2D) wet monodisperse and poly disperse foams are investigated by the quasi-static simulation. We set the same inlet velocity on the cross section of the foam channel and then focus on the elastic-plastic deformation of the 2D wet foam according to the strain caused by the foam flow. The gas fraction in foam is referred to as foam quality and the effects of foam quality on the shear modulus, bubble dynamics, and stress-strain properties are obtained by the simulation. In the elastic domain, the shear modulus of monodisperse foam decreases exponentially with foam quality, but for the polydisperse foam, the shear modulus tends to increase. The shear banding of the polydisperse foam appears in the low strain and disappears gradually as the strain and foam quality increase. We adopt shear rate to represent the change rate of average bubbles displacements versus y-coordinates and find that the distribution of shear rate in the y-direction changes with iteration. Additionally, energy of the foam is stored and dissipated with the elastic-plastic deformation of the foam. The average shear stress generated by the foam structure and the initial increment of normal stress difference caused by the elastic deformation increase with the increase of foam quality. [ABSTRACT FROM AUTHOR]

In this research, we studied supercritical water oxidation (SCWO) of a pesticide wastewater under a wide range of operation conditions in two reaction plants. The results show that reaction temperature, oxidant coefficient (OC), and residence time (t) can improve the wastewater XCOD (removal efficiency of chemical oxygen demand). The residence time and OC have important influences on XCOD at higher reaction temperatures (>500 °C). It is significant to increase the preheating rate for the XCOD improvement of the pesticide wastewater in SCWO. XCOD and XTN (removal efficiency of total nitrogen) are 99.42% and 86.70% at 600 °C, 25 MPa, OC = 3.0 and t = 2.0 min, respectively. More than 92wt% total organic carbon (TOC) and 86.70 wt% total nitrogen in the wastewater are converted into CO2 and N2 under the above conditions, respectively. Inconel 625 can be used as the reactor material in the wastewater SCWO plant, and its corrosion rate is approximately 0.6mm/year at 600 °C, 25 MPa and OC = 3.0 conditions. We also primarily design a 100 t/d SCWO plant for the tested pesticide wastewater treatment on the basis of accomplished investigations. SCWO together with traditional wastewater treatment methods is proposed to harmlessly dispose the complicated wastewater. This information is valuable for guiding the large-scale SCWO plant design for pesticide wastewater treatment. [ABSTRACT FROM AUTHOR]

Reactor corrosion and plugging problems have hindered the commercialization of supercritical water oxidation (SCWO) for wastewater purification. The use of transpiring wall reactor (TWR) is an effective means to overcome the above two problems by forming a protective water film on the internal surface of the reactor to aviod contacting corrosive species and precipitated organic salts. This work mainly aims to objectively review experimental investi-gations and numerical simulation results concerning TWR. Subsequent investigations for parameters optimizations of TWR are also proposed in order to ultimately build effective regulation methods of obtaining excellent water film properties. All this information is very important in guiding the structure design and operation parameters optimization of TWR. [ABSTRACT FROM AUTHOR]

In this article, an experimental study on rheological properties and proppant transport performance of the GRF-CO2 system is performed by using a large-scale high-temperature and high-pressure foam fracturing fluid test system with the correlations for fracturing fluid rheological parameters, critical settling velocity and proppant settling velocity obtained. Research results show that the effective viscosity decreases with increasing temperature and shear rate. The effective viscosity increases with increasing foam quality in foamed cases, and decreases with increasing foam quality in unfoamed cases. The temperature and foam quality effect on parameters of the rheological properties of the fracturing fluid is larger than the pressure in various influencing factors. The critical settling velocity increases with the rise in temperature in foaming cases, and decreases with the rise in foam quality and sand ratio. The reunion phenomenon happens after the sand ratio is more than 25%. The correlations for GRF-CO2 fracturing fluid rheological index, rheological coefficient, final proppant settling velocity in the solution and the critical settling velocity have been obtained with an average error of calculation less than 14%. [ABSTRACT FROM AUTHOR]

The supercritical water oxidation (SCWO) technology has shown high efficiency in Lurgi coal gasification wastewater treatment. However, the cost of oxygen and energy consumption become the major limiting factors for the industrial operation as the oxygen used is always excessive. In this paper, we proposed two schemes that combined the SCWO and gasification processes to recover the excessive oxygen and heat. The combined processes were simulated by Aspen Plus software and their economic values were also analyzed. In scheme (I), the SCWO and gasification processes were combined by a pressure reducer. The depressurized SCWO effluent was directly used as a gasification agent. In this scheme, zero wastewater discharge can be realized and all the excessive oxygen and heat were completely recovered. In scheme (II), the SCWO and gasification processes were combined by a heat exchanger. The heat of the SCWO effluent was recovered through the heat exchange with another introduced cold fluid. The oxygen was recovered in the oxygen recovery section set behind the SCWO process, in which a byproduct of industrial grade liquefied CO2 was produced. The recovery efficiencies of oxygen and heat were 99.35% and 90.76%, respectively. For a single gasifier with steam of 27 t h-1 (673.15 K) and oxygen of 6.73 t h-1 (373.15 K) as gasification agents, the investment in scheme (I) and scheme (II) were 8500 and 103500 €, respectively, and the recovered profit of materials and heat were 730 and 691 € h-1, respectively [ABSTRACT FROM AUTHOR]

Copper complex ethylenediamine tetraacetic acid (Cu(II)-EDTA) was oxidized in supercritical water in a continuous tubular reactor at temperatures 420-500°C, residence times 57-144s, and a pressure 25MPa. The major carbon containing products were CO2 and CO. The TOC conversions increased steadily with reaction temperature and residence time, and the yield of CO can be effectively reduced at elevating temperatures. Ammonia was determined to be the main refractory nitrogen-containing intermediate, whose oxidation was supposed to be enhanced by the copper in Cu(II)-EDTA. In addition, the copper transformed into copper oxides (CuO and CU2O), and was removed from the Cu(II)-EDTA solution with high efficiency. Based on the experimental results and the analysis of reaction pathways, a global Arrhenius kinetic model was proposed to predict the removal of TOC and the yield of the intermediates NH3 and CO. With this kinetic model, a computational fluid dynamic (CFD) model of the tubular reactor was implemented to assist the experimental study. The composition profiles of TOC, CO, and CO2 along the reactor were simulated and compared with the experimental results. Operating parameters, reaction temperature and oxygen flow rate, were optimized based on the simulation results. [ABSTRACT FROM AUTHOR]

Supercritical water oxidation (SCWO) is a promising technology to deal with organic wastes. Nowadays, we have successfully constructed the first SCWO pilot scale plant of China with a specific reactor configuration and optimized system compositions to treat sewage sludge. In this report, the existing problems and corresponding solutions concerning corrosion, plugging and high running cost in SCWO are introduced systematically. The detailed system components, evident properties, advanced control methods and primary experiment results of the pilot scale plant are described objectively. Moreover, a simple economical comparison with incineration is carried out and subsequently in-depth works are also proposed for further promoting the commercial application of the plant. The information should be helpful for designing and constructing SCWO plant to dispose sewage sludge or other organic wastewaters. [ABSTRACT FROM AUTHOR]

Phenol, a substance difficult to be gasified, is often an intermediate product from biomass gasification in supercritical water. In this study, 1 wt % phenol is gasified in supercritical water with different oxidation coefficients (0 ≤ n≤ 0.8) at 430−550 °C, 25 MPa in a continuous tubular-flow reaction plant with or without 0.1 wt % Na2CO3. The results show that TOC (total organic carbon) removal rate and COD (chemical oxygen demand) removal rate of reactor effluent will rise with the increase of oxidation coefficient and reaction temperature. When nrises from 0.3 to 0.8 at 500 °C, hydrogen yield and hydrogen molar fraction will first increase and then decrease. They reach their respective maximum values of 0.245 mol/mol and 46.2% at n= 0.6 with the residence time of 2.96 min. There is an appropriate oxidation coefficient for obtaining the highest hydrogen yield for phenol supercritical water partial oxidative gasification (SWPO). Na2CO3can serve as a catalyst or an additive for phenol SWPO. When 0.1 wt % Na2CO3is added, hydrogen yield is near 0.477 mol/mol at n= 0.6, 500 °C with the residence time of 2.96 min. Furthermore, the potential conversion pathways for phenol SWPO with Na2CO3catalyst are also proposed. [ABSTRACT FROM AUTHOR]

A model is constructed to evaluate the electronic conductance of an electron beam in double-gap coupling cavity resonator. The electronic conductance is studied both analytically and numerically. The analytical expression for the electronic conductance is derived based on the nonlinear space-charge wave theory, and it is also presented as a function of modulation coefficient in detail. It is shown that the analytic results of electronic conductance are in reasonable agreement with the numerical simulations. In addition, the simulated results of the beam susceptance are also given, and the results show that the change of susceptance with modulation coefficient is very small. [ABSTRACT FROM AUTHOR]

The design of an electron optics system for a W-band sheet beam klystron was described. An elliptically cylindrical electron gun and wiggler focusing structure were adopted to produce and guide a 80-kV 4-A sheet beam with an elliptical cross section of 10 × 0.4 mm. The wiggler focusing principle was reviewed and a practical structure was presented. MAFIA was used to simulate the structure. The simulation showed that the electron beam transmission attained 100% over 100 mm in distance with a fill factor that is less than 0.6. [ABSTRACT FROM AUTHOR]