Functionalized porphyrin and porphyrin containing trifluoromethyl with ferrocene were synthesized.The UV-Vis absorption bands of porphyrin with an electron withdrawing trifluoromethyl group were blue-shifted and those of porphyrin with an electron donating ferrocenyl group were red-shifted.The porphyrin containing ferrocenyl exhibited strong fluorescence quenching compared with those containing trifluoromethyl.The quenching efficiency of diferrocenyl porphyrin was about 66% with a quantum yield Φ f of 0.08.These results indicated that there was a strong interaction between the excited state of porphyrin and ferrocene, which was further confirmed by the time-resolved fluorescence measurements.The electrochemical studies indicated that it was difficult to lost electron for the stable porphyrin with an electron withdrawing trifluoromethyl.However, the porphyrin with a ferrocenyl group was oxidized easily to lost electron and was a good electron donor.The research is supposed to provide some theoretical basis for this kind of compound using in donor-acceptor system.
Background and hypothesis: RAGE and its ligands have been implicated in pathogenesis of ischemia/reperfusion injury. We hypothesized that RAGE expression in ischemic myocardium can be imaged in mic...
Abstract Our previous finding revealed that the Wnt10b RNA expression of osteoporotic adipose‐derived stem cells (OP‐ASCs) with impaired osteogenic capacity was significantly reduced than that of ASCs. There are no ideas that the relationship between the OP‐ASCs' impaired osteogenic potential and Wnt10b expression. This study aimed to indicate the potential molecular mechanisms and functional role of Wnt10b in OP‐ASCs, as well as to investigate a potential application to reverse the OP‐ASCs' impaired osteogenic differentiation potential. The OP‐ASCs and ASCs were harvested from the inguinal fat of osteoporosis (OP) mice with bilateral ovariectomy (OVX) and normal mice. qPCR and WB were used to detect the different levels of the expression of the Wnt10b RNA in both OP‐ASCs and ASCs. Lentiviral‐mediated regulation of Wnt10b expression was employed for OP‐ASCs, and the detection of the expression levels of key molecules in the Wnt signalling pathway and key osteogenic factors was performed through qPCR and WB in vitro experiments. The capacity of OP‐ASCs to osteogenesis was determined using alizarin red staining. Lastly, the repair effect of the BCP scaffolds incorporating modified OP‐ASCs on the critical‐sized calvarial defects (CSCDs) in OP mice was scanned and detected by micro‐computed tomography, haematoxylin and eosin staining, Masson's trichrome staining and immunohistochemistry. First, we discovered that both the RNA and protein expression levels of Wnt10b were significantly lower in OP‐ASCs than that in ASCs. In vitro experiments, upregulation of Wnt10b could activate the Wnt signalling pathway, and increase expression of β‐catenin, Lef1, Runx2 and osteopontin (Opn), thereby enhancing the osteogenic ability of OP‐ASCs. In addition, the OP‐ASCs with Wnt10b ‐overexpressing could promote the repair of CSCD in osteoporotic mice with increasing new bone volume, bone mineral density, and increased expression of Opn in new bone in vivo. Taken together, overexpression of Wnt10b could partially facilitate the differentiation of OP‐ASCs towards osteogenesis and accelerated the healing of bone defects by activating the Wnt/β‐catenin signalling pathway in vitro and in vivo experiments. This study confirmed the important role of Wnt10b in regulating the osteogenic differentiation capability of OP‐ASCs and indicated Wnt10b could be a potential therapeutic target for reversing the impaired osteogenic capabilities of OP‐ASCs to therapy bone defects of OP patients.
Abstract The folding behaviors and mechanisms of large multidomain proteins have remained largely uncharacterized, primarily because of the lack of appropriate research methods. To address these limitations, novel mechanical folding probes have been developed that are based on antiparallel coiled‐coil polypeptides. Such probes can be conveniently inserted at the DNA level, at different positions within the protein of interest where they minimally disturb the host protein structure. During single‐molecule force spectroscopy measurements, the forced unfolding of the probe captures the progress of the unfolding front through the host protein structure. This novel approach allows unfolding pathways of large proteins to be directly identified. As an example, this probe was used in a large multidomain protein with ten identical ankyrin repeats, and the unfolding pathway, its direction, and the order of sequential unfolding were unequivocally and precisely determined. This development facilitates the examination of the folding pathways of large proteins, which are predominant in the proteasomes of all organisms, but have thus far eluded study because of the technical limitations encountered when using traditional techniques.
Ultra-fine ZrB_2/SiC composite ceramic powders were synthesized at temperatures from 1300℃to 1700℃by carhothermal reduction using zirconium dioxide,boric acid,silica sol and carbon black as raw materials. The influences of synthesis temperature and reactant ratio on the phase composition,micro morphology and particle size of the composite powders were investigated by XRD and SEM.The results show that the completeness of carhothermal reduction for the synthesis of high purity ZrB_2/SiC composite powders was needed of over dosage of boric acid(molar ratio of ZrO_2 and B_2O_3 was 1:1.5) when synthesized at 1650℃for 1 h.The composite powders had an average particle size of 0.4μm,and different particle shapes after prepared at different temperatures.With the increase of synthesis temperature.the whisker and rod particles gradually reduced while ball particles increased.
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