ABSTRACT
Tin-based perovskite solar cells (T-PSCs) are introduced as the next generation of valid and environment-friendly photovoltaic (PV) cells for near-future commercialization. However, there are some issues limiting T-PSCs including their instability, low efficiency, and use of toxic processing solvents. Among all these barriers, instability and early aging under thermal stress conditions are considered as significant challenges to the development of the T-PSCs. In this study, the impact of different temperature levels on the performance of a T-PSC is investigated over time. It is observed that early degradation of the device occurs at higher temperatures. For timely detection of the early aging, an accurate adaptive estimation of the series resistance is obtained in the equivalent single-diode circuit model of the T-PSC. It is shown that the trend of changes in the series resistance is a reliable indication of the aging process in the T-PSC. Finally, a mathematical index is derived for early aging detection based on the relative variation of the gradient from its minimum value in the linear regression analysis. The proposed approach could be utilized for timely detection of early aging conditions and protection of the device from permanent damage.
ABSTRACT
BACKGROUND: Pediatric infectious disease is one of the main problems in cancerous children that treat by chemotherapy drugs. Thus, study in this regard is necessary. The aim of this study was to evaluate antimicrobial properties of ethanolic extract of Ziziphus Jujuba fruits against different infectious pathogens. MATERIALS AND METHODS: This study is descriptive. In vitro antimicrobial activity of extract was assessed on gram negative and gram positive bacteria as well as fungi. The antimicrobial activity was tested by Radial Diffusion Assay (RDA) and Minimal Inhibitory Concentration (MIC) methods. RESULTS: The results showed a wide antimicrobial activity of the extract against the microbes studied. Escherichia coli was the most susceptible to the extracts among tested microorganisms for which the MIC was 0.65±0.22 mg/ml. Amongst the bacterial strains investigated, Staphylococcus aureus was the most resistant strain with MIC of 2.26±0.68 mg/ml. The ethanolic extract also showed antimicrobial activity on the fungi studied as no growth was observed in 2.35±0.38 and 2.86±0.7 mg/ml concentration for Candida albicans and Aspergillus fumigatus, respectively. The results of qualitive and quantitative test are well indicative of the extract effective activity against the microbes mentioned. CONCLUSION: Confirming the potential antimicrobial activities of crude extract of Ziziphus Jujuba fruits, this study suggested that ethanolic extracts of this plant is appropriate candidate for treatment of microbial infections, especially pediatric infectious diseases.
