Characteristics of silicon etching by silicon chloride ions

Tomoko Ito and Kazuhiro Karahashi, Journal of Vacuum Science & Technology A 31, 031301 (2013) https://doi.org/10.1116/1.479342

Investigation of Method for Measuring Soil Shearing Resistance by Using SR-2 Type Soil Resistance Measuring Instruments

SR-2 type soil resistance measuring instruments have been used from about 1965 in Japan as measuring tools for field use to measure soil dynamic values. But the SR-2 type method for measuring soil shearing resistance, which has the outer diameter of 100 mm, the inner diameter of 60 mm and the height of vanes of 10 mm and takes the half of shearing torque as the shearing resistance in the bottom of annulus, neglects the side effect. Therefore, various discussions have been done. This study made it clear that the effect of annular inner side was extremely small because the soil was pushed up and broken out and the effect of outer side were fairly large and shearing was brought about. This side effect appeared larger in cohesion (the ratio of 1.83 ±　0.48 to the control) than in internal friction angle. And also, this study presents such method for improving without harming the feature of SR-2 type as measuring tools for field use as that it is most suitable to cut away previously the outer side of annulus with a cutter knife

Formation and desorption of nickel hexafluoroacetylacetonate Ni(hfac)2on a nickel oxide surface in atomic layer etching processes

Abdulrahman H. Basher, Marjan Krstić, Takae Takeuchi, Michiro Isobe, Tomoko Ito, Masato Kiuchi, Kazuhiro Karahashi1, Wolfgang Wenzel, and Satoshi Hamaguchi, Journal of Vacuum Science & Technology A 38:2, (2020); licensed under a Creative Commons Attribution (CC BY) license

Stability of hexafluoroacetylacetone molecules on metallic and oxidized nickel surfaces in atomic-layer-etching processes

Abdulrahman H. Basher, Marjan Krstić, Takae Takeuchi, Michiro Isobe, Tomoko Ito, Masato Kiuchi, Kazuhiro Karahashi, Wolfgang Wenzel, and Satoshi Hamaguchi, Journal of Vacuum Science & Technology A 38:2, (2020); licensed under a Creative Commons Attribution (CC BY) license

Effects of hydrogen ion irradiation on zinc oxide etching

Mechanisms of zinc oxide (ZnO) etching by hydrocarbon plasmas were investigated both experimentally and theoretically with the use of a mass-selected ion beam system and first-principle quantum mechanical (QM) simulation based on the density functional theory. The mass-selected ion beam experiments have shown that the sputtering yield of ZnO increases by a pretreatment of the ZnO film by energetic hydrogen (H) ion injections prior to heavy ion bombardment, suggesting that chemically enhanced etching of ZnO by hydrocarbon plasmas is closely related to hydrogen storage and/or formation of damage in the ZnO layer by energetic hydrogen injections. In this study, the effects of hydrogen storage in ZnO are examined. First-principle QM simulation of ZnO interacting with H atoms has shown that H atoms in ZnO form hydroxyl (OH) groups (or partially convert ZnO to ZnOH), which results in the weakening or breaking of the Zn-O bonds around H atoms and thus makes the ZnO film more prone to physical sputtering. The formation of hydroxyl groups in ZnO is also expected to occur in ZnO etching by hydrocarbon plasmas and increase its sputtering yields over those by inert-gas plasmas generated under similar conditions.H. Li et al., Journal of Vacuum Science & Technology A 35, 05C303 (2017) https://doi.org/10.1116/1.498271

Platelet-Activating Factor Induces TLR4 Expression in Intestinal Epithelial Cells: Implication for the Pathogenesis of Necrotizing Enterocolitis

Necrotizing enterocolitis (NEC) is a leading cause of morbidity and mortality in neonatal intensive care units, however its pathogenesis is not completely understood. We have previously shown that platelet activating factor (PAF), bacteria and TLR4 are all important factors in the development of NEC. Given that Toll-like receptors (TLRs) are expressed at low levels in enterocytes of the mature gastrointestinal tract, but were shown to be aberrantly over-expressed in enterocytes in experimental NEC, we examined the regulation of TLR4 expression and signaling by PAF in intestinal epithelial cells using human and mouse in vitro cell lines, and the ex vivo rat intestinal loop model. In intestinal epithelial cell (IEC) lines, PAF stimulation yielded upregulation of both TLR4 mRNA and protein expression and led to increased IL-8 secretion following stimulation with LPS (in an otherwise LPS minimally responsive cell line). PAF stimulation resulted in increased human TLR4 promoter activation in a dose dependent manner. Western blotting and immunohistochemical analysis showed PAF induced STAT3 phosphorylation and nuclear translocation in IEC, and PAF-induced TLR4 expression was inhibited by STAT3 and NFκB Inhibitors. Our findings provide evidence for a mechanism by which PAF augments inflammation in the intestinal epithelium through abnormal TLR4 upregulation, thereby contributing to the intestinal injury of NEC