[en] Anion exchange reactions in lead halide perovskites provide post-treatment methods to functionalize and modulate their photoelectric properties. However, the mechanism of anion exchange reactions is still fiercely debated. Herein, by investigating time-dependent in situ PL spectra after mixing CsPbBr3 and CsPb(Br0.09/I0.91)3 perovskite nanocrystals (PNCs), the anion exchange process is divided into three stages, i.e. photon reabsorption process, initial anion exchange, and adequate anion exchange. This model is broadly applicable to different situations, ignoring the mixing order or molar ratios between Br and I. This work provides a dynamic model to describe the anion exchange of CsPbX3 PNCs, which will not only add fundamental knowledge to the stability of PNCs, but also guide the post-treatment of PNCs
Journal
New Journal of Chemistry; ISSN 1144-0546; 
; v. 44(no.47); p. 20592-20599
; v. 44(no.47); p. 20592-20599
[en] Highlights: • UNC5B facilitates osteogenic differentiation of human adipose-derived stem cells. • It does so by modulation bone morphogenetic protein signaling. • UNC5B may be useful for bone tissue engineering and therapy for bone defects. UNC-5 netrin receptor B (UNC5B) is a dependence receptor of netrin-1 that plays an essential role in mediating angiogenesis and tumorigenesis. Despite its significant roles, there is limited knowledge about the role played by UNC5B in osteogenesis. In the present study, we first demonstrated that UNC5B was required for osteogenic differentiation of human adipose-derived stem cells (hASCs), both in vitro and in vivo. We also found that mechanistically, UNC5B promotes osteogenic differentiation by activating bone morphogenetic protein signaling. These findings point to a new important function of UNC5B and provide a potential basis for hASCs-mediated bone regeneration.
Journal
Biochemical and Biophysical Research Communications; ISSN 0006-291X; ; CODEN BBRCA9; v. 495(1); p. 1167-1174
; CODEN BBRCA9; v. 495(1); p. 1167-1174
[en] Highlights: • Osteogenic differentiation of human adipose-derived stem cells was studied. • ARL4C is a regulator of osteogenic differentiation in vitro and in vivo. • ARL4C knockdown downregulates Wnt non-canonical pathway components. • Wnt canonical pathway protein LRP6 is downregulated in ARL4C knockdown cells. ADP-ribosylation factor-like 4C (ARL4C) has been shown to play an important role in cholesterol secretion, microtubule dynamics, and cell morphological changes. However, its role in osteogenesis has not been explored. In this study, we found that ARL4C is downregulated during the osteogenic differentiation of human adipose derived stem cells (hASCs). Knockdown of ARL4C suppresses osteogenesis of hASCs in vitro and in vivo. We demonstrate that ARL4C knockdown likely attenuates osteogenesis of hASCs through inhibition of the Wnt signaling pathway. These results provide new insights into the mechanisms of osteogenic differentiation and provide a potential molecular target for bone tissue engineering.
Journal
Biochemical and Biophysical Research Communications; ISSN 0006-291X; ; CODEN BBRCA9; v. 497(1); p. 256-263
; CODEN BBRCA9; v. 497(1); p. 256-263
[en] Highlights: • A high-accuracy and ship-based observation system was integrated and applied to observe during sailing. • High-precision mole fraction distributions of CO2, CO, CH4 and N2O over the Yellow Sea and the East China Sea. • The source regions of the gases were traced through the NOAA HYSPLIT Model. • The emission characteristics of the gases in different source regions were analyzed by two estimates. During a cruise of the survey vessel Dongfanghong II on the Yellow Sea and the East China Sea in the spring of 2017 we performed accurate measurements of the mole fractions of carbon dioxide (CO2), methane (CH4), carbon monoxide (CO) and nitrous oxide (N2O) using two types of Cavity Ring-Down Spectrometers (CRDS). The spatial variations of the mole fraction of the four trace gases were very similar. The emission sources of these gases were divided into several regions by using the NOAA HYSPLIT model. Then we analyzed the variations of the ratios of the mole fraction enhancements between every pair of trace gases downwind of these source areas. The ratios showed that the distributions of these trace gases over the Yellow Sea and the East China Sea in the spring were mainly caused by the emissions from Eastern China. The much higher enhancement ratio of ΔCO/ΔCO2 and the lower ratio of ΔCH4/ΔCO observed in the air parcels from big cities like Beijing and Shanghai indicated high CO emission from the cities during our time of observation. Compared with the values of NOAA's Marine Boundary Layer (MBL), the ratios of the averages in the air coming from the Northern sector (Russia) were on average closer to the MBL, and the air that stayed over the Yellow Sea and the East China Sea was a mixture of emissions from wide regional areas. The highly variable N2O data of the air from Qingdao and Shanghai showed much more fluctuation.
Journal
[en] Highlights: • Performance of a strategy of constructing a novel tissue-engineered bone (TEB). • Simvastatin could release in a sustained manner after incorporated in the TEB. • This novel TEB could promote the bone formation capability of hASCs more effectively. To repair bone defects, we evaluate the in-vitro and in-vivo osteogenic activities of a novel tissue-engineered bone (TEB) by elaborately combining biomimetic calcium phosphate (BioCaP) granules with internally-incorporated simvastatin (SIM) and human adipose-derived stem cells (hASCs). First, we constructed BioCaP with SIM internally incorporated (SIM-BioCaP). Then we characterized the morphology and chemical composition of SIM-BioCaP. The release kinetics of SIM was monitored in vitro spectroscopically. Thereafter, we explored the in-vitro cellular responses of hASCs to SIM-BioCaP by performing scanning electron microscopy observation, proliferation assay, alkaline phosphatase (ALP) activity assay, alizarin red staining and real-time PCR. Finally, we investigated the in-vivo osteogenic activities of the novel TEB in a subcutaneous bone induction model in nude mice. We found that SIM was successfully incorporated internally in BioCaP and showed a slow release manner without significantly affecting the attachment and proliferation of hASCs. The released SIM from BioCaP could significantly enhance the proliferation, ALP activities, mineralized nodules formation and osteogenic genes of hASCs. The in-vivo tests showed this TEB could induce new bone formation while the other groups could not. Taken together, the present data show that this novel TEB represented a very promising construct to treat critical-volume bone defects.
Journal
Biochemical and Biophysical Research Communications; ISSN 0006-291X; ; CODEN BBRCA9; v. 495(1); p. 1264-1270
; CODEN BBRCA9; v. 495(1); p. 1264-1270