Search

This paper develops the architecture of a digital PWM controller for application in multiphase voltage regulation modules (VRMs). In this context, passive current sharing and VRM transient response with nonzero controller delay are analyzed. A scheme for sensing a combination of the VRM output voltage and output current with a single low-resolution window analog-to-digital converter (ADC) is proposed. The architecture and IC implementation of a digital PWM (DPWM) generation module, using a ring-oscillator-multiplexer scheme, is discussed. Experimental results from a prototype VRM and a partial controller IC implementation are presented. Index Terms--Analog-digital conversion, current sharing, digital control, digital modulation, inductance, integrated circuits, power conversion, pulse-width modulation, ring oscillators, transient analysis, voltage control.

Objective: To investigate the effect of humidified high-flow nasal cannula oxygen therapy (HFNC) on the application effect and respiratory functional recovery of stable COPD patients., Methods: The data of 116 patients with stable COPD treated in our hospital from March 2019 to January 2021 were analyzed retrospectively. Among them, 54 patients treated with conventional oxygen therapy (COT) were enrolled into the control group (CG), and the remaining 62 treated with HFNC were divided to the experimental group (EG). The clinical efficacy and adverse reactions of both groups were assessed, and the blood gas analysis indexes pH, PaO 2 , PaCO 2 , respiratory function indexes FEV1, FEV1%, FEV1/FVC, quality of life and motor recovery were compared., Results: After treatment, compared with the CG, the FEV1, FEV1% and FEV1/FVC in the EG were obviously higher (P<0.05). Besides, the pH and PaO 2 in the EG were markedly higher (P<0.05), while PaCO 2 was lower (P<0.05). The total effective rate, SGRQ scores and 6MWT in the EG were markedly higher than those in the CG (P<0.05), while the incidence of adverse reactions in the EG was lower (P<0.05)., Conclusion: HFNC can improve respiratory function and quality of life of stable COPD patients, with higher safety., (AJTR Copyright © 2022.)

Myocardial fibrosis (MF) plays an important part in cardiovascular diseases. The main cytological characteristics of MF is the increased number of myofibroblasts, which have multiple sources such as EMT, EndMT, myeloid progenitors, monocytes, and fibrocytes. Recent data showed that pericytes may represent a major source of myofibroblasts in kidney fibrosis. Valproic acid (VPA) is a kind of short-chain fatty acid. It was reported in recent studies that VPA regulates gene expression and influences various signal pathways. HDACs inhibitors can hinder the growth of tumor cells and differentiation of stem cells. And little is known about the effects of HDACs inhibitors on myofibroblasts transdiffererntiaton. This study focused on the role of HDACs in pericyte-myofibroblast trans -differentiation and how HDACs inhibitor VPA influenced proliferation, migration, viability and myofibroblast trans -differentiation of pericytes for the first time. Rat cardiac fibrosis model was induced by Ang II. Immunohistochemistry was employed to examine cardiac fibrosis and flow cytometry was used to analyze whether inflammatory cells involve VPA-induced trans -differentiation. Pericytes proliferation, migration and differentiation to myofibroblasts were performed to examine the role of VPA on pericyte trans -differentiation. Immunoblot and qPCR were applied to identify the signal transduction involving in VPA-induced trans -differentiation. In vivo study showed that HDAC inhibitor VPA blocks cardiac fibrosis, and inflammation inhibition was not involved in this process. VPA treatment inhibited Ang II pericyte proliferation, migration and transdifferentiation to myofibroblast. Furthermore, the inhibition of α-SMA expression by VPA was related to reduce phosphorylation of ERK, and a pharmacological inhibitor of MEK suppressed Ang II-induced α-SMA expression. HDAC4 knockdown resulted in inhibiting Ang II-mediated α-SMA expression as well as the phosphorylation of ERK. Moreover, the inhibitors of protein phosphatase 2A and 1 (PP2A and PP1) restored the Ang II-stimulated α-SMA expression from the inhibitory effect of VPA. Together, the current data indicate that the differentiation of pericytes to myofibroblasts is HDAC4 dependent and requires phosphorylation of ERK., Competing Interests: None.