電子ビーム・プラズマ系における不安定波動に関する研究

第1章 緒言 第2章 電子ビーム･プラズマ系における波動の分散特性 第3章 電子ビーム･プラズマ系における不安定モードの遷移 第4章 不安定波動のサブハーモニクスの観測 第5章 総括Made available in DSpace on 2012-07-04T00:19:16Z (GMT). No. of bitstreams: 1 kasuya.pdf: 15340900 bytes, checksum: 7de813a202fe1a264c2ea685e0516b6b (MD5) Previous issue date: 1991-03-2

miR-200b Precursor Can Ameliorate Renal Tubulointerstitial Fibrosis

Members of the miR-200 family of micro RNAs (miRNAs) have been shown to inhibit epithelial-mesenchymal transition (EMT). EMT of tubular epithelial cells is the mechanism by which renal fibroblasts are generated. Here we show that miR-200 family members inhibit transforming growth factor-beta (TGF-beta)-induced EMT of tubular cells. Unilateral ureter obstruction (UUO) is a common model of EMT of tubular cells and subsequent tubulointerstitial fibrosis. In order to examine the role of miR-200 family members in tubulointerstitial fibrosis, their expression was investigated in the kidneys of UUO mice. The expression of miR-200 family miRNAs was increased in a time-dependent manner, with induction of miR-200b most pronounced. To clarify the effect of miR-200b on tubulointerstitial fibrosis, we injected miR-200b precursor intravenously. A single injection of 0.5 nM miR-200b precursor was sufficient to inhibit the increase of collagen types I, III and fibronectin in obstructed kidneys, and amelioration of fibrosis was confirmed by observation of the kidneys with Azan staining. miR-200 family members have been previously shown to inhibit EMT by reducing the expression of ZEB-1 and ZEB-2 which are known repressors of E-cadherin. We demonstrated that expression of ZEB-1 and ZEB-2 was increased after ureter obstruction and that administration of the miR-200b precursor reversed this effect. In summary, these results indicate that miR-200 family is up-regulated after ureter obstruction, miR-200b being strongly induced, and that miR-200b ameliorates tubulointerstitial fibrosis in obstructed kidneys. We suggest that members of the miR-200 family, and miR-200b specifically, might constitute novel therapeutic targets in kidney disease

Ion energy distribution measurements of low-energy ion beams extracted from a hot cathode DC ion source

Ion energy distribution function (IEDF) of low-energy ion beams extracted from a hot cathode DC ion source have been measured and analyzed using a retarding potential analyzer. Measurements revealed that the height of the IEDF peaks increased in proportion to the discharge current of the ion source. In terms of downstream gas pressure, an optimum value of the height of the IEDF peak was observed at 0.13 Pa at different discharge currents. Full width at half maximum measurements showed an increase in energy spread (ΔE) with increasing discharge current. With a discharge current of 30 mA and 0.13 Pa pressure, ΔE was almost constant against the change in extraction potentials from 20 to 60 V. Typical ΔE was at most 10% of the extraction beam energy. The ion beam current density was in the mA/cm2 range

Observation of Subharmonic Wave in an Electron-Beam Plasma System

Subharmonic wave excitation associated with Langmuir wave in an electron-beam plasma system is studied by using a Double-Plasma device in detail. It is shown that subharmonic waves are excited when the ratio of beam to plasma densities is small. The amplitude of the Langmuir wave is also found to become small with an increase in that of the subharmonics