A Pd‐catalyzed enantioselective linear‐allylic alkylation of vinyl benzoxazinanones with a series of 3‐substituted oxindoles was reported in the presence of a chiral oxamide‐phosphine ligand ...(COAP−Bn) under mild reaction conditions. A series of optically active multifunctional 3,3′‐disubstituted oxindole derivatives bearing a quaternary stereogenic center and a linear aryl amino side chain were respectively obtained in 55–98% yields with 96–99% ee for 3‐(hetero)aryl substituted oxindoles. The developed protocol demonstrates that the COAP ligands could serve as a privileged chiral ligand to construct diverse chiral 3,3‐disubstituted oxindole compounds with various quaternary stereogenic centers, such as aza‐, thio‐ or all‐carbon quaternary stereogenic centers. The salient features of the method include broad substrate scope, N‐protecting group free, base‐free, and high regio‐ and enantioselectivity.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Low‐dimensional devices with different photoconductive effects attract much attention in optoelectronics. In this work, negative photoconductivity (NPC) monolayer graphene photodetectors are ...fabricated by chemical vapor deposition (CVD), and a positive photoconductivity (PPC) photodetector is realized by decorating perovskite FAPbI3 quantum dots prepared by a simple and cost‐effective non‐polar solvent synthesis method on a graphene surface. The graphene‐based photodetector exhibits an NPC characteristic, which is attributed to the absorption and desorption of water molecules on the graphene surface. The responsivity of the photodetector with an NPC characteristic is −0.86 A W−1 under intense ultraviolet light irradiation, and the detectivity is −2.45 × 109 Jones. The FAPbI3 quantum dots/graphene photodetector with a PPC feature has a responsivity of 8.03 A W−1 and a detectivity of 1.89 × 1010 Jones under the irradiation of ultraviolet light of 365 nm and 55.3 mW cm−2 intensity. Due to the intense light absorption of perovskite combined with the extremely high mobility of graphene, photodetectors have high exciton separation and photocurrents when the devices are irradiated by ultraviolet light. Individual photodetectors are successfully created with NPC and PPC effects; the critical analysis for the different photoconductive mechanisms is provided, which will benefit the development of future multifunctional systems.
Negative photoconductivity monolayer graphene photodetectors are fabricated by chemical vapor deposition, and positive photoconductivity photodetectors are realized by perovskite FAPbI3 quantum dots with a simple and cost‐effective non‐polar solvent synthesis method on the graphene surface. The combination of photodetectors with negative photoconductivity and positive photoconductivity effects can be simultaneously applied on a chip that benefits future intelligent Internet of Things systems.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Photodetectors based on reduced graphene oxide (rGO) have attracted much attention owing to their simple and low‐cost fabrication process. However, the aggregation and defects of rGO flakes still ...limit the performance of rGO photodetectors. Controlling the composition of rGO has become a vital factor for its prospective applications. For example, the interconnection between rGO and polymers for modified morphologies of rGO films leads to an enhanced performance of devices. In this work, a practical approach to engineer surface uniformity and enhance the performance of a photodetector by modifying the rGO film with hydrophilic polymers poly(vinyl alcohol) (PVA) is reported. Compared with the rGO photodetector, the on/off ratio for the PVA/rGO photodetector shows 3.5 times improvement, and the detectivity shows 53% enhancement even when the photodetector is operated at a low bias of 0.3 V. This study provides an effective route to realize PVA/rGO photodetectors with a low‐power operation which shows promising opportunities for the future development of green systems.
A practical approach to enhance the performance of a reduced graphene oxide (rGO) photodetector by modifying the rGO film with poly(vinyl alcohol) (PVA) is reported. Compared with the rGO photodetector, the on/off ratio for the PVA/rGO photodetector shows 3.5 times improvement, and the detectivity shows 53% enhancement at a low operating bias of 0.3 V.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
All-solution-processed reduced graphene oxide (rGO)-based flexible photodetectors (PDs) with asymmetric electrode structures of Ag nanowires (NWs) - Cu NWs are demonstrated for stable photodetection ...in weak-light environments. At first, we aimed to optimize the fabrication parameters of rGO layers for minimum roughness and high uniformity according to the field emission scanning electron microscope (FESEM) images; the average absorbance of optimal rGO layers is <inline-formula> <tex-math notation="LaTeX">\sim </tex-math></inline-formula>17.4% from 400 to 1600 nm. Additionally, compared to Ag NWs - Ag NWs and Cu NWs - Cu NWs electrodes, rGO PDs with Ag NWs-Cu NWs asymmetric electrodes showed a higher photocurrent-to-dark-current ratio (PDCR) (<inline-formula> <tex-math notation="LaTeX">\sim </tex-math></inline-formula>6), which was due to the improved carrier transport with using Ag and Cu as cathodes and anodes. Furthermore, the highest photoresponsivity (5.5 mA/W) and detectivity (<inline-formula> <tex-math notation="LaTeX">D^{\ast} </tex-math></inline-formula>) (<inline-formula> <tex-math notation="LaTeX">\sim {1}\times {10}^{{9}} </tex-math></inline-formula> cm Hz<inline-formula> <tex-math notation="LaTeX">^{{{1}/{2}}} </tex-math></inline-formula>/W) of rGO PDs with Ag NWs - Cu NWs electrodes have been measured and evaluated at 8 V bias. This work demonstrates the significant potential of all-solution processed rGO-based flexible PDs for high-performance and low-cost photosensing applications.
Disordered lipid metabolism plays an essential role in both the initiation and progression of alcoholic fatty liver disease (AFLD), and fatty acid β-oxidation is increasingly considered as a crucial ...factor for controlling lipid metabolism. Hif-2α is a member of the Hif family of nuclear receptors, which take part in regulating hepatic fatty acid β-oxidation. However, its functional role in AFLD and the underlying mechanisms remain unclear.
Hif-2α was upregulated in EtOH-fed mice and EtOH-treated AML-12 cells. Inhibition or silencing of Hif-2α led to increased fatty acid β-oxidation and BNIP3-dependent mitophagy. Downregulation of Hif-2α activates the PPAR-α/PGC-1α signaling pathway, which is involved in hepatic fatty acid β-oxidation, by mediating BNIP3-dependent mitophagy, ultimately delaying the progression of AFLD.
Hif-2α induces liver steatosis, which promotes the progression of AFLD. Here, we have described a novel Hif-2α-BNIP3-dependent mitophagy regulatory pathway interconnected with EtOH-induced lipid accumulation, which could be a potential therapeutic target for the prevention and treatment of AFLD.
A chiral oxalamide phosphine (COAP)-Pd-catalyzed asymmetric cascade formal 4 + 1 annulation was developed between racemic vinyl benzoxazinones and N-tosylhydrazone sodium salts. The corresponding ...trans-2,3-disubstituted indoline products with contiguous stereogenic centers were obtained in good yields with high diastereo- and enantioselectivity. The catalytic outcomes and computational DFT study showed that the biphilic transformation proceeded by a dynamic kinetic asymmetric transformation (DYKAT) process. The enantio-determining step is a stereoselective migratory insertion of Pd(ii)-carbene into a pendant chiral π-allylpalladium-COAP complex, followed by reductive elimination to fulfill the annulation.
An asymmetric linear selective allylic alkylation of vinylaziridines with 3-aryl oxindoles has been developed by using a chiral oxamide-phosphine (COAP-Bn-OMe-p)/palladium complex in methanol, which ...furnished a wide variety of 3,3-disubstituted oxindole derivatives in good yields with excellent regio- and enantioselectivities.
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IJS, KILJ, NUK, PNG, UL, UM
Currently, the drugs used in clinical to treat psoriasis mainly broadly suppress cellular immunity. However, these drugs can only provide temporary and partial symptom relief, they do not cure the ...condition and may lead to recurrence or even serious toxic side effects. In this study, we describe the discovery of a novel potent CDK8 inhibitor as a treatment for psoriasis. Through structure-based design, compound 46 was identified as the most promising candidate, exhibiting a strong inhibitory effect on CDK8 (IC50 value of 57 nM) along with favourable inhibition against NF-κB. Additionally, it demonstrated a positive effect in an in vitro psoriasis model induced by TNF-α. Furthermore, this compound enhanced the thermal stability of CDK8 and exerted evident effects on the biological function of CDK8, and it had favourable selectivity across the CDK family and tyrosine kinase. This compound showed no obvious inhibitory effect on CYP450 enzyme. Further studies confirmed that compound 46 exhibited therapeutic effect on IMQ-induced psoriasis, alleviated the inflammatory response in mice, and enhanced the expression of Foxp3 and IL-10 in the dorsal skin in vivo. This discovery provides a new strategy for developing selective CDK8 inhibitors with anti-inflammatory activity for the treatment of psoriasis.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Plasmid-carrying Saccharomyces cerevisia (W303-1BpYeDP60/G/ADS) and genome-transformed S. cerevisia (W303-1BrDNA:ADS), both harboring amorpha-4,11-diene synthase (ADS) gene were constructed to ...investigate the production of amorpha-4,11-diene. The recombinant plasmid pYeDP60/G/ADS that harbors the ADS gene was transformed into S. cerevisiae W303-1B, resulting in the engineered yeast W303-1BpYeDP60/G/ADS, which contains multi-copies of the plasmid. The ADS gene expression cassette was obtained by PCR amplification of the pYeDP60/G/ADS template, and then introduced into S. cerevisiae W303-1B to obtain the engineered yeast W303-1BrDNA:ADS, in which the ADS gene was integrated into the rDNA locus of the yeast genome through the homologous recombination. GC-MS analysis confirmed that both of the engineered yeasts could produce amorpha-4,11-diene. Moreover, the amorpha-4,11-diene yield of W303-1BpYeDP60/G/ADS was higher than that of W303-1BrDNA:ADS. Southern blot analysis showed that there is only one co
Amorpha-4,11-diene synthase (ADS) can convert farnesyl pyrophosphate (FPP) to amorpha-4, 11-diene, a precursor of artemisinin. ADS plays an important role in the biosynthesis of artemisinin. This ...review summarizes the molecular biology and metabolic engineering study of ADS in recent years. The genomic DNA and its cDNA sequences of amorpha-4, 11-diene synthase were cloned from Artemisia annua L. The cDNA encoding amorpha-4, 11-diene synthase contains a 1 641 bp open reading frame coding for 546 amino acids. ADS shows a broad pH optimum and an absolute requirement for divalent metal ions as cofactors. The specificity of ADS to the substrates and products is not high and the formation of amorpha-4, 11-diene by ADS from FPP is achieved by an initial 1, 6-closure with subsequent 1, 10-closure. The ADS cDNA cloned from Artemisia annua L, or totally synthesized by PCR, was introduced into different hosts including E. coli, S. cerevisiae, Nicotiana tabacum L. Arabidopsis thaliana and A. nidulans resulting in varied
