MPPT oscillations minimization in PV system by controlling non-linear dynamics in SEPIC DC-DC converter

Solar PV power generation has achieved rapid growth in developing countries which has many merits such as absence of noise, longer life, no pollution, less time for installation, and ease of grid interface. A maximum power point tracking circuit (MPPT) consists of DC-DC power electronics converters that are used to improve the energy attainment from solar PV array. This paper presents a detailed analysis to control of chaos, a non-linear dynamic in SEPIC DC-DC converter interfaced solar PV system, to minimize the oscillations near to MPP. In SEPIC DC-DC converter, the input inductor current is continuous and capable of sweeping the whole I-V curve of a PV module from open circuit voltage (Voc) to short circuit current (Isc) operating points. To trace the true maximum power point and to nullify the oscillations near to MPP, the yield output voltage needs to ensure period-1 operation

MicroRNA Involvement in Immune Activation During Heart Failure

Heart failure is one of the common end stages of cardiovascular diseases, the leading cause of death in developed countries. Molecular mechanisms underlying the development of heart failure remain elusive but there is a consistent observation of chronic immune activation and aberrant microRNA (miRNA) expression that is present in failing hearts. This review will focus on the interplay between the immune system and miRNAs as factors that play a role during the development of heart failure. Several studies have shown that heart failure patients can be characterized by a sustained innate immune activation. The role of inflammatory signaling is discussed and TLR4 signaling, IL-1β, TNFα and IL-6 expression appears to coincide with the development of heart failure. Furthermore, we describe the implication of the renin angiotensin aldosteron system in immunity and heart failure. In the past decade microRNAs (miRNAs), small non-coding RNAs that translationally repress protein synthesis by binding to partially complementary sequences of mRNA, have come to light as important regulators of several kinds of cardiovascular diseases including cardiac hypertrophy and heart failure. The involvement of differentially expressed miRNAs in the inflammation that occurs during the development of heart failure is still subject of investigation. Here, we summarize and comment on the first studies in this field and hypothesize on the putative involvement of certain miRNAs in heart failure. MicroRNAs have been shown to be critical regulators of cardiac function and inflammation. Future research will have to point out if dampening the immune response, and the miRNAs associated with it, during the development of heart failure is a therapeutically plausible route to follow