Chronic inflammatory bowel diseases (IBDs) are associated with differential expression of genes involved in inflammation and tissue remodelling. We surveyed the expression profile of apoptosis-related microRNAs by real-time quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR) in a dextran sulphate sodium (DSS) murine model of colitis. We found that miR-150 was strongly elevated, whereas c-Myb, a transcription factor and a target gene of miR-150, was significantly reduced in colon tissue after DSS treatment. Interestingly, elevation of miR-150 and down-regulation of c-Myb were also observed in human colon with active ulcerative colitis compared to the normal colon. Supporting the observation of DSS treatment inducing colonic cell apoptosis, Bcl-2, an anti-apoptotic protein known to be regulated by c-Myb, was reduced in colon tissue of DSS-treated mice. Furthermore, forced expression of pre-miR-150 in colonic epithelial HT29 cells strongly elevated miR-150 levels and decreased c-Myb and Bcl-2 levels, thus enhancing cell apoptosis induced by serum deprivation. Together, the present study presents the first evidence that miR-150 and its targeting of c-Myb may serve as a new mechanism underlying the colonic epithelial disruption in DSS-induced murine experimental colitis and in active human IBD.
Purpose
The purpose of this study is to improve the performance of AISI 430 stainless steel (430 SS) in increasing its oxidation resistance, suppressing coating spalling and cracking, sustaining appropriate conductivity and blocking Cr evaporation as an interconnect material for intermediate temperature solid oxide fuel cells; a protective co-contained coating is formed onto stainless steel via the surface alloying process and followed by thermal oxidation.
Design/methodology/approach
In this work, oxidation behavior of coated specimen is studied during isothermal and cyclic oxidation measurements. Moreover, the conductivity is also investigated by area specific resistance (ASR) measurement.
Findings
Co-contained spinel layer shows an outstanding performance in preventing oxidation and improving conductivity compared with uncoated specimens. The protective spinel coating also reduces the ASR for coated specimen (0.0576O cm2) as compared to the uncoated specimen (1.87296O cm2) after isothermal oxidation.
Originality/value
The probable mechanism of co-contained alloy converting into spinel and the spinel transfer electron is presented.
Purpose
The purpose of this paper is to improve the surface electrical conductivity and corrosion resistance of AISI 430 stainless steel (430 SS) as bipolar plates for proton exchange membrane fuel cells (PEMFCs), a protective Nb-modified layer is formed onto stainless steel via the plasma surface diffusion alloying method. The effect of diffusion alloying time on electrochemical behavior and surface conductivity is evaluated.
Design/methodology/approach
In this work, the surface electrical conductivity and corrosion resistance of modified specimen are evaluated by the potentiodynamic and potentionstatic polarization tests. Moreover, the hydrophobicity is also investigated by contact angle measurement.
Findings
The Nb-modified 430 SS treated by 1.5 h (1.5Nb) presented a lower passivation current density, lower interfacial contact resistance and a higher hydrophobicity than other modified specimens. Moreover, the 1.5 Nb specimen presents a smoother surface than other modified specimens after potentionstatic polarization tests.
Originality/value
The effect of diffusion alloying time on electrochemical behavior, surface conductivity and hydrophobicity of modified specimen is evaluated. The probable anti-corrosion mechanism of Nb-modified specimen in simulated acid PEMFC cathode environment is presented.
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