A major focus of studies that center on regeneration of the periodontium is to determine the efficacy of the use of polypeptide growth factors. Platelet-derived growth factor has been reported to be a possible agent for clinical use. PDGF has various isoforms. Therefore, we decided to study the mitogenic and chemotactic responses of human periodontal ligament (PDL) cells to recombinant human PDGF-AB, AA, and BB. Addition of each isoform of PDGF to in vitro mitogenesis assays induced PDL cell proliferation in a dose-dependent manner. The maximum mitogenic effect was evident at the concentration of 100 ng/mL. In these assays, PDGF-BB was found to be the most potent mitogen. PDGF-AB elicited an intermediate response, and PDGF-AA was the least effective. The results of chemotaxis assays closely parallel those of the mitogenesis assays. PDGF-BB exhibited the most potent chemotactic effect. The maximal effect was observed at 10 ng/mL. The findings of these experiments indicate that PDGF-BB is more effective than the other isoforms in promoting mitogenesis and chemotaxis of PDL cells in vitro, and may therefore be a suitable ethical pharmaceutical for use in periodontal regeneration procedures.
One of the most challenging tasks in wildlife conservation and management is to clarify how spatial variation in land cover due to anthropogenic disturbance influences wildlife demography and longterm viability. To evaluate this, we compared rates of survival and population growth by woodland caribou (Rangifer tarandus caribou) from 2 study sites in northern Ontario, Canada that differed in the degree of anthropogenic disturbance because of commercial logging and road development, resulting in differences in predation risk due to gray wolves (Canis lupus). We used an individual-based model for population viability analysis (PVA) that incorporated adaptive patterns of caribou movement in relation to predation risk and food availability to predict stochastic variation in rates of caribou survival. Field estimates of annual survival rates for adult female caribou in the unlogged (¯= x 0.90) and logged (¯= x 0.76) study sites recorded during 2010-2014 did not differ significantly (P > 0.05) from values predicted by the individual-based PVA model (unlogged:x = 0.87; logged:¯= x 0.79). Outcomes from the individual-based PVA model and a simpler stage-structured matrix model suggest that substantial differences in adult survival largely due to wolf predation are likely to lead to long-term decline of woodland caribou in the commercially logged landscape, whereas the unlogged landscape should be considerably more capable of sustaining caribou. Estimates of population growth rates (λ) for the 2010-2014 period differed little between the matrix model and the individual-based PVA model for the unlogged (matrix modelx = 1.01; individual-based modelx = 0.98) and logged landscape (matrix modelx = 0.88; individual-based modelx = 0.89). We applied the spatially explicit PVA model to assess the viability of woodland caribou across 14 woodland caribou ranges in Ontario. Outcomes of these simulations suggest that woodland caribou ranges that have experiencedThis is an open access article under the terms of the Creative Commons Attribution-NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes. significant levels of commercial forestry activities in the past had annual growth rates <0.89, whereas caribou ranges that had not experienced commercial forestry operations had population growth rates >0.96. These differences were strongly related to regional variation in wolf densities. Our results suggest that increased wolf predation risk due to anthropogenic disturbance is of sufficient magnitude to cause appreciable risk of population decline in woodland caribou in Ontario.
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Photoelectrochemical (PEC) water splitting has been regarded as a promising technology for sustainable hydrogen production. The development of efficient photoelectrode materials is the key to improve the solar-to-hydrogen (STH) conversion...
Sluggish oxygen evolution kinetics are one of the key limitations of bismuth vanadate (BiVO 4 ) photoanodes for efficient photoelectrochemical (PEC) water splitting. To address this issue, we report a vanadium oxide (VO x ) with enriched oxygen vacancies conformally grown on BiVO 4 photoanodes by a simple photoassisted electrodeposition process. The optimized BiVO 4 /VO x photoanode exhibits a photocurrent density of 6.29 mA cm À 2 at 1.23 V versus the reversible hydrogen electrode under AM 1.5 G illumination, which is ca. 385 % as high as that of its pristine counterpart. A high charge-transfer efficiency of 96 % is achieved and stable PEC water splitting is realized, with a photocurrent retention rate of 88.3 % upon 40 h of testing. The excellent PEC performance is attributed to the presence of oxygen vacancies in VO x that forms undercoordinated sites, which strengthen the adsorption of water molecules onto the active sites and promote charge transfer during the oxygen evolution reaction. This work demonstrates the potential of vanadium-based catalysts for PEC water oxidation.
An efficient ultrasound-assisted aqueous two-phase extraction and enrichment process for phenylethanoid glycosides from Cistanche deserticola Y. C. Ma stems was developed in this work. An ethanol/ammonium sulfate system was chosen for the aqueous two-phase system due to its fine partitioning and recycling behaviors. Single-factor experiments and response surface methodology were used to optimize the process parameters of the ultrasound-assisted aqueous two-phase extraction. The optimal conditions were as follows: a salt concentration of 23.5%, an ethanol concentration of 20%, an extraction time of 37 min, an extraction temperature of 30°C, a liquid/solid ratio of 30:1 w/w, and an ultrasound power of 300 W. Under the above conditions, the extraction yields of echinacoside and acteoside (the main components of phenylethanoid glycosides) reached 5.35 and 6.22 mg/g dry material weight, respectively. The contents of echinacoside and acteoside in the extracts reached 27.56 and 30.23 mg/g, respectively, which were 2.46- and 2.58-fold higher than the amounts obtained in ultrasound-assisted extraction. In conclusion, ultrasound-assisted aqueous two-phase extraction was an efficient, ecofriendly, and economical method, and it may be a promising technique for extracting and enriching bioactive components from plants.
The development of nanomedicines provides new opportunities for the treatment of atherosclerosis (AS) due to their great advantages such as the improved drug solubility, enhanced bioavailability and reduced side effects. Despite these advantages, nanomedicines are still facing some challenges. The problems remain in the short circulation life, lack of specific targeting and poor drug release controllability. In order to overcome the shortages of conventional nanomedicines, the combination of biomimetic strategy with smart nanoagents has been proposed. In light with the high reactive oxygen species (ROS) level in AS microenvironment and the fact that macrophages play a critical role in the pathogenesis of AS, we fabricated ROS-responsive biomimetic nanoparticles (NPs), which camouflaged macrophage membrane (MM) on ROS-responsive NPs loaded with rapamycin (RNPs) for potential application in AS therapy. The resulting ROS-responsive biomimetic NPs (MM/RNPs) exhibited favorable hydrodynamic size with negative surface charge, retained the functional proteins from MM, and showed ROS-responsive drug release. Because of the biomimetic camouflaging on surface, MM/RNPs could effectively escape from macrophages uptake and target to inflammatory endothelial cells. Meanwhile, MM/RNPs could inhibit the proliferation of macrophages and smooth muscle cells in vitro. Furthermore, the MM-coated NPs were found to be nontoxic in both cytotoxicity assay and in vivo toxicity evaluation. Consequently, these results demonstrated that MM/RNPs could be a potential candidate of drug delivery system for safe and effective anti-AS applications.
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