The impact of the digital economy on creative industries development: Empirical evidence based on the China.

Digital economy has become a "new engine" that driving global economic growth. Nevertheless, numerous controversies persist regarding whether and how digital economy can facilitate the development of emerging industries. Thus, this paper investigates how digital economy affects creative industries development in China and whether innovation efficiency mediates this relationship. Drawing upon a panel data set containing 29 Chinese provinces from 2012 to 2019, an econometric model is constructed for empirical analysis. We find that digital economy significantly promotes creative industries development, and innovation efficiency plays a partial mediating role between digital economy and creative industries development. According to the influence mechanism, the digital economy of various regions could promote the creative industries development by improving the innovation efficiency. Finally, relevant suggestions were put forward from the expanding application paths, improving regional innovation efficiency, and creating an innovative environment.

The Interactive Relationship between Street Centrality and Land Use Intensity-A Case Study of Jinan, China.

It is of great significance to study the interactive relationship between urban transportation and land use for promoting the healthy and sustainable development of cities. Taking Jinan, China, as an example, this study explored the interactive relationship between street centrality (SC) and land use intensity (LUI) in the main urban area of Jinan by using the spatial three-stage least squares method. The results showed that the closeness centrality showed an obvious "core-edge" pattern, which gradually decreased from the central urban area to the edge area. Both the betweenness centrality and the straightness centrality showed a multi-center structure. The commercial land intensity (CLUI) showed the characteristics of multi-core spatial distribution, while the residential land intensity (RLUI) and public service land intensity (PLUI) showed the characteristics of spatial distribution with the coexistence of large and small cores. There was an interactive relationship between SC and LUI. The closeness centrality and straightness centrality had positive effects on LUI, and LUI had a positive effect on closeness centrality and straightness centrality. The betweenness centrality had a negative impact on LUI, and LUI also had a negative impact on betweenness centrality. Moreover, good location factors and good traffic conditions were conducive to improving the closeness and straightness centrality of the regional traffic network. Good location factors, good traffic conditions and high population density were conducive to improving regional LUI.

[Development of a motor neurons-specific fluorescence reporter system].

Human induced pluripotent stem cells (hiPSCs) have the potential to differentiate into multiple cell types. Motor neurons (MNs) differentiated from hiPSCs are important models of many motor neuron diseases. To simplify the identification of MNs, lentivirus vectors were used to transfer MNs-specific promoter HB9 and red fluorescent protein (RFP) gene into hiPSCs-derived human neural stem cells (hNSCs). Stable positive cells hNSCs-HB9-RFP-Puro were obtained after antibiotic selection. Subsequently, the positive cell line was infected with lentiviruses LV-Ngn2-Sox11-GFP and LV-Isl1-Lhx3-Hygro, which overexpressed the MNs differentiation transcription factor, and differentiated to MNs directly. Differentiated mature MNs showed neuron-like structure, expressed RFP and neuron-related markers ß-tubulin and choline acetyltransferase (ChAT) under the control of the MNs-specific promoter HB9. The fluorescence reporter system provides a visual method for directed differentiation and identification of MNs, and may promote the applications of MNs in disease models and drug screening.

Synthesis, anti-microbial and anti-inflammatory activities of 18ß-glycyrrhetinic acid derivatives.

Thirteen 18ß-glycyrrhetinic acid (GA) derivatives were obtained by reduction at C-11 position, oxidation at C-3 position and condensation at C-2 position of GA. Anti-microbial activity evaluation indicated that compounds 04, 05, 10, 13 and 14 showed more potent inhibitory activity against Staphylococcus aureus subsp. aureus, Staphylococcus epidermidis, Staphylococcus aureus than GA, especially compound 10, the inhibitory activity against Staphylococcus epidermidis was equaled with Ampicillin. Moreover, in vivo experiments exhibited that compound 10 also has anti-inflammatory effect, which could decrease about 59.69% TPA-induced ear edema of mice with the gavage treatment of 40.0 mg/mL. Immunohistochemistry results revealed that the effect of inhibition was related to inhibition of TPA-induced upregulation of the pro-inflammatory cytokines TNF-α and IL-1ß. Furthermore, compound 10 also significantly decreased the expression level of p65 in NF-κB signaling pathway. In general, compound 10, both with antibacterial and anti-inflammatory activities, was expected to become a promising bio-functional agent.

Synthesis and biological evaluation of coumarin derivatives as α-glucosidase inhibitors.

In this study, two series of coumarin derivatives 5a∼i and 6a∼i were synthesized, and their inhibitory activity against α-glucosidase was determined. The results indicated that most of the synthesized derivatives exhibited prominent inhibitory activities against α-glucosidase. Among them, compounds 5a and 5b showed the strongest inhibition with the IC50 values of 19.64 µM and 12.98 µM, respectively. Enzyme kinetic studies of compounds 5a and 5b proved that their inhibition was reversible and a mixed type. The KI and KIS values of compound 5a were calculated to be 27.39 µM and 13.02 µM, respectively, and the corresponding values for compound 5b being 27.02 µM and 13.65 µM, respectively. The docking studies showed that compound 5b could be inserted into the active pocket of α-glucosidase and form hydrogen bonds with LYS293 to enhance the binding affinity.

Development of a simple, rapid and high-throughput fluorescence polarization immunoassay for glycocholic acid in human urine.

In this paper, a simple, rapid and high-throughput fluorescence polarization immunoassay (FPIA) based on polyclonal antibodies (PAb) is described for the determination of glycocholic acid (GCA) in human urine. Three fluorescein-labeled GCA (tracers) with different structures and spacer bridges were synthesized and purified by thin-layer chromatography (TLC). The structure effect of tracers on the assay was investigated and the sensitivity of best tracer in the optimized FPIA demonstrated an IC50 value of 306 ng/mL. The working range of FPIA was 36 ∼ 2 600 ng/mL and the limit of detection (LOD) was 9 ng/mL. The developed FPIA was time-saving that could be completed within 10 min. Human urine samples spiked with GCA were analyzed by this method, followed by confirmation with commercial enzyme immunoassay analysis (EIA). Excellent recoveries and correlation between these two methods were observed (R2 = 0.996), suggesting the developed FPIA could be applied to screening of GCA in human urine samples without complicated cleanup.

Biotinylated single-chain variable fragment-based enzyme-linked immunosorbent assay for glycocholic acid.

Glycocholic acid (GCA) has been identified as a novel selective and sensitive biomarker for hepatocellular carcinoma (HCC). In this work, a recombinant antibody, scFv-G11, which was shown previously to have selective reactivity for GCA, was labeled with biotin using a chemical and an enzymatic method, respectively. The enzymatic method proved superior giving sensitive scFv-biotin preparations. Based on biotinylated scFv against GCA and a biotin-streptavidin system for signal amplification, an indirect competitive biotin-streptavidin-amplified enzyme-linked immunosorbent assay (BA-ELISA) has been established for the sensitive and rapid detection of GCA. Several physiochemical factors that influenced assay performance, such as organic cosolvent, ionic strength, and pH, were studied. Under the optimized conditions, the indirect competitive BA-ELISA based on the obtained biotinylated scFv antibodies indicated that the average concentration required for 50% inhibition of binding (IC50) and the limit of detection (LOD) for GCA were 0.42 µg mL-1 and 0.07 µg mL-1, respectively, and the linear response range extended from 0.14 to 1.24 µg mL-1. Cross-reactivity of biotinylated scFv antibodies with various bile acid analogues was below 1.89%, except for taurocholic acid. The recoveries of GCA from urine samples via this indirect competitive BA-ELISA ranged from 108.3% to 131.5%, and correlated well with liquid chromatography-electrospray tandem mass spectrometry (LC-MS/MS), which indicated the accuracy and reliability of biotinylated scFv-based ELISA in the detection of GCA in urine samples. This study also demonstrates the broad utility of scFv for the development of highly sensitive immunoassays.

Synthesis and biological evaluation of novel ursolic acid analogues as potential α-glucosidase inhibitors.

Ursolic acid (UA) is a major pentacyclic triterpenoid in plants, vegetables and fruits, which has been reported to have a potential anti-diabetic activity. Despite various semi-synthetic ursolic acid derivatives already described, new derivatives still need to be designed and synthesized to further improve the anti-diabetic activity. In the present study, two series of novel UA derivatives, were synthesized and their structures were confirmed. The enzyme inhibition activities of semi-synthesized analogues against α-glucosidase were screened in vitro. The results indicated that most of UA derivatives showed a significant inhibitory activity, especially analogues UA-O-i with the IC50 values of 0.71 ± 0.27 µM, which was more potential than other analogues and the positive control. Furthermore, molecular docking studies were also investigated to verify the in vitro study. Structure modification at the C-3 and C-2 positions of UA was an effective approach to obtain the desired ligand from UA, whose structure was in accordance with the active pocket. Besides, suitable hydrophobic group at the position of C-2 might play an important role for the docking selectivity and binding affinity between the ligand and the homology modelling protein. These results could be helpful for designing more potential α-glucosidase inhibitors from UA in the future.

Synthesis and Evaluation of Novel Triterpene Analogues of Ursolic Acid as Potential Antidiabetic Agent.

Ursolic acid (UA) is a naturally bioactive compound that possesses potential anti-diabetic activity. The relatively safe and effective molecule intrigued us to further explore and to improve its anti-diabetic activity. In the present study, a series of novel UA analogues was synthesized and their structures were characterized. Their bioactivities against the α-glucosidase from baker's yeast were determined in vitro. The results suggested that most of the analogues exhibited significant inhibitory activity, especially analogues 8b and 9b with the IC50 values of 1.27 ± 0.27 µM (8b) and 1.28 ± 0.27 µM (9b), which were lower than the other analogues and the positive control. The molecular docking and 2D-QSAR studies were carried out to prove that the C-3 hydroxyl could interact with the hydrophobic region of the active pocket and form hydrogen bonds to increase the binding affinity of ligand and the homology modelling protein. Thus, these results will be helpful for understanding the relationship between binding mode and bioactivity and for designing better inhibitors from UA analogues.