BackgroundH. pylori infection may trigger Smad7 and NFκB expression in the stomach, whereas probiotics promote gastrointestinal health and improve intestinal inflammation caused by pathogens. This study examines if probiotics can improve H. pylori-induced gastric inflammation by inactivating the Smad7 and NFκB pathways.ResultsChallenge with H. pylori increased IL-8 and TNF-α expressions but not TGF-β1 in MKN45 cells. The RNA levels of Smad7 in AGS cells increased after H. pylori infection in a dose-dependent manner. A higher dose (MOI 100) of L. acidophilus pre-treatment attenuated the H. pylori-induced IL-8 expressions, but not TGF-β1. Such anti-inflammatory effect was mediated via increased cytoplasmic IκBα and depletion of nuclear NFκB. L. acidophilus also inhibited H. pylori-induced Smad7 transcription by inactivating the Jak1 and Stat1 pathways, which might activate the TGF-β1/Smad pathway. L. acidophilus pre-treatment ameliorated IFN-γ-induced Smad7 translation level and subsequently reduced nuclear NF-κB production, as detected by western blotting.ConclusionsH. pylori infection induces Smad7, NFκB, IL-8, and TNF-α production in vitro. Higher doses of L. acidophilus pre-treatment reduce H. pylori-induced inflammation through the inactivation of the Smad7 and NFκB pathways.
SUMMARYThis letter presents a single-stage soft-switched full-bridge AC/DC converter for low-voltage/high-current output applications. A phase-shifted method with a variable frequency control is used to regulate the DC bus voltage and the output voltage of the single-stage AC/DC converter. The proposed circuit topology and control scheme exhibit superior performances (i.e. high power factor, high-efficiency, and ring-free features). Correspondingly, a laboratory prototype, 500 W 5V/100A AC/DC converter, is implemented to verify the feasibility of the proposed design.
This paper presents a module-integrated isolated solar micro-inverter. The studied grid-tied micro-inverters can individually extract the maximum solar power from each photovoltaic (PV) panel and transfer to the AC utility system. A harmonic suppression technique is used to reduce the DC-bus capacitance. Electrolytic capacitors are not needed in the studied solar micro-inverter. High conversion efficiency, high maximum power point tracking accuracy and long lifespan can be achieved. The operation principles and design considerations of the studied PV inverter are analyzed and discussed. A laboratory prototype is implemented and tested to verify its feasibility. This paper presents a grid-tied isolated solar micro-inverter. A harmonic suppression technique is used to reduce the DC-bus capacitance. E-Cap is not needed, and the lifetime of the studied module-integrated solar inverter can be then prolonged. High conversion efficiency, high MPPT accuracy and low THD characteristics can be also achieved. In the experimental verifications, the MPPT accuracy of the developed solar micro-inverter is around 0.99, while the measured CEC efficiency can be up to 92.18%.
582H.-J. CHIU ET AL.
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