A series of bipolar hosts, namely, 5-(2-(9H-carbazol-9-yl)-phenyl)-1,3-dipyrazolbenzene (o-CzDPz), 5-(3-(9H-carbazol-9-yl)-phenyl)-1,3-dipyrazolbenzene (m-CzDPz), 5-(9-phenyl-9H-carbazol-3-yl)-1,3-dipyrazolbenzene (3-CzDPz), and 5-(3,5-di(9H-carbazol-9-yl)-phenyl)-1,3-dipyrazolbenzene (mCPDPz), are developed for phosphorescent and thermally activated delayed fluorescence (TADF) organic light-emitting diodes (OLEDs). They are designed by selecting pyrazole as n-type unit and carbazole as p-type one. The triplet energy (E(T)), the frontier molecular orbital level, and charge transporting abilities, are adjusted by varying the molar ratio of pyrazole to carbazole and the linking mode between them. They have high E(T) values of 2.76-3.02 eV. Their electroluminescence performance is evaluated by fabricating both phosphorescent and TADF devices with blue or green emitters. The m-CzDPz hosted blue phosphorescent OLEDs achieves high efficiency of 48.3 cd A(-1) (26.8%), the 3-CzDPz hosted green phosphorescent device exhibits 91.2 cd A(-1) (29.0%). The blue and green TADF devices with 3-CzDPz host also reach high efficiencies of 26.2 cd A(-1) (15.8%) and 41.1 cd A(-1) (13.3%), respectively. The excellent performance of all these OLEDs verifies that these pyrazole-based bipolar compounds are capable of being universal host materials for OLED application. The influence of molar ratio of n-type unit to p-type one and the molecular conformation of these hosts on their device performance is discussed and interpreted.
Resveratrol is now gaining much attention because of its pharmacological properties. Polygonum cuspidatum has the highest content of resveratrol in plants and is the best material offering resveratrol. However, the content of resveratrol in P. cuspidatum is much lower compared with its glycoside polydatin. In this study, enzymatic transformation of polydatin to resveratrol by piceid-β-D-glucosidase from Aspergillus oryzae sp. 100 was investigated. The biotransformation conditions were optimized. Under the optimized conditions of 60 °C, pH 5.0, substrate concentration of 40 g/L and piceid-β-D-glucosidase activity of 5 U/mL, enzymatic transformation of polydatin from P. cuspidatum was successfully performed, during which 22.5 g/L of resveratrol was produced after reacting for 4 h, with the substrate conversion rate of 2 g/h/U of piceid-β-D-glucosidase. A feasible and environment friendly process of enzymatic transformation of polydatin to resveratrol was developed, which provides a promising and competitive alternative for the production of resveratrol.
BackgroundPretreatment is an essential step in the enzymatic hydrolysis of biomass for bio-ethanol production. The dominant concern in this step is how to decrease the high cost of pretreatment while achieving a high sugar yield. Fungal pretreatment of biomass was previously reported to be effective, with the advantage of having a low energy requirement and requiring no application of additional chemicals. In this work, Gloeophyllum trabeum KU-41 was chosen for corn stover pretreatment through screening with 40 strains of wood-rot fungi. The objective of the current work is to find out which characteristics of corn stover pretreated with G. trabeum KU-41 determine the pretreatment method to be successful and worthwhile to apply. This will be done by determining the lignin content, structural carbohydrate, cellulose crystallinity, initial adsorption capacity of cellulase and specific surface area of pretreated corn stover.ResultsThe content of xylan in pretreated corn stover was decreased by 43% in comparison to the untreated corn stover. The initial cellulase adsorption capacity and the specific surface area of corn stover pretreated with G. trabeum were increased by 7.0- and 2.5-fold, respectively. Also there was little increase in the cellulose crystallinity of pretreated corn stover.ConclusionG. trabeum has an efficient degradation system, and the results indicated that the conversion of cellulose to glucose increases as the accessibility of cellulose increases due to the partial removal of xylan and the structure breakage of the cell wall. This pretreatment method can be further explored as an alternative to the thermochemical pretreatment method.
Regulation of lipid accumulation in Schizochytrium sp. ATCC 20888 in response to different nitrogen sources was investigated in this study. Nitrogen sources had important effects on the cell growth, lipid accumulation, and docosahexaenoic acid (DHA) percentage in total fatty acids (TFAs). Compared with sole organic nitrogen source, the combination of yeast extract and monosodium glutamate (MSG) greatly enhanced the biomass, total lipids, and DHA percentage in TFAs, but inorganic nitrogen source addition decreased the biomass and total lipids. The results showed that lipids began to accumulate rapidly with the depletion of dissolved ammonia in broth, and the time required for nitrogen exhaustion was extended with increasing nitrogen source concentration. Furthermore, the analysis of isocitrate dehydrogenase (ICDH) and malic enzyme (ME) activities during fermentation process provided insight for the revelation of regulation mechanism of lipid accumulation in Schizochytrium sp. ATCC 20888 in response to nitrogen exhaustion in broth. Practical applications: DHA, an essential nutrient for human health, is widely used in infant formula and functional foods. DHA production by Schizochytrium sp. has recently received extensive attention as the commercial source of DHA to substitute marine fish oil. Nitrogen sources in the cultivation of Schizochytrium sp. have important effects on the cell growth, lipid accumulation, and DHA percentage in TFAs. This study provides valuable guidance for nitrogen source selection for efficient DHA‐rich lipids production by Schizochytrium sp. The combination of yeast extract and MSG enhances the biomass, lipid yield, and DHA percentage in TFAs, but inorganic nitrogen source addition decreases the biomass and lipid yield. The results in this study have important significance in understanding lipid accumulation regulation in Schizochytrium sp. in response to nitrogen sources and providing guidance for DHA‐rich lipid production enhancement.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.