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Silk fibroin (SF)–chondroitin sulfate (CS)-hybrid hydrogels (HHGs) containing kartogenin (KGN) were synthesized by the induction of di-tyrosine bonds, using enzymatic crosslinking in SF/CS blend solution. Then, physical crosslinking was performed to optimize the HHG properties. The results showed that the increasing of the β-sheet content as side effect of physical crosslinking from 10% to 40% affects KGN accumulative release percentage almost three times. Biological investigations using C28/I2 human chondrocyte cell line showed that the presence of KGN, CS, and optimized β-sheets content improved cell supporting behavior of HHG. Finally, KGN loaded HHG might be a promising candidate for cartilage repair. Schematic representation of fabrication of the dual crosslinked hybrid hydrogel containing silk fibroin and chondroitin sulfate by enzymatic crosslinking and physical crosslinking method for kartogenin release. Enzymatic crosslinking: shaping di-tyrosine formation bond between silk fibroin phenol groups and locking physically chondroitin sulfate between silk fibroin β-sheets. Physical crosslinking with water and/or ethanol treatments end up in increased β-sheets content. [ABSTRACT FROM AUTHOR]

Degradation efficiency of 4-bromo-2-chlorophenol (BCP) containing both chlorine and bromine substituents in Co/PMS process was investigated in the light of a wide range of substrate, oxidant, catalyst concentrations and pH value. The effects of chloride ion (Cl−) on degradation kinetics, total organic carbon (TOC) removal and intermediates formation during BCP depletion in Co/PMS system were studied. The kinetics results demonstrated that the dual effect of Cl− on BCP depletion in Co/PMS system due to different mechanisms involved. High concentrations of Cl− (>5 mM) can significantly promote the degradation of BCP, but did inhibit BCP mineralisation to a certain extent which was closely related to Cl− content. High degradation rates but lower mineralisation rates were found in the laboratory experiments, owing to the fact that BCP was mainly transformed to new halogenated intermediates instead of complete mineralisation. Gas chromatograph-mass spectrometer (GC-MS) data verified that a series of chlorinated by-products were formed during BCP decomposition process involving of the participation of Cl−. The proposed degradation pathways of BCP and its derivatives in presence of Cl− were discussed on the basis of intermediate products including the undesirable halogenated by-products recognised by GC-MS. These results might offer some new perspectives on the transformation fates of BCP by utilising Co/PMS regent. [ABSTRACT FROM AUTHOR]

This study examined the associations of long-term exposure to ambient fine particulate matter (PM2.5) compositions/ozone with methylation of peripheral brain-derived neurotrophic factor (BDNF) promoters. A total of 101 participants were recruited from a cohort in Shijiazhuang, Hebei province, China. They underwent baseline and follow-up surveys in 2011 and 2015. DNA methylation levels were detected by bisulfite-PCR amplification and pyrosequencing. Participants' three-year average levels of PM2.5 compositions and ozone were estimated. Bayesian kernel machine regression (BKMR) models were used to examine the joint effects of pollutants on methylation levels. Exposure to PM2.5 compositions and ozone mixtures at the 75th percentile was associated with increased methylation levels at CpG2 of BDNF promoter (203%, 95% CI: 89, 316) than the lowest level of exposure, and sulfate dominated the effect in the BKMR models.Our findings provide clues to the epigenetic mechanisms for the associations of PM2.5 compositions and ozone with BDNF. [ABSTRACT FROM AUTHOR]

To provide a theoretical basis for reducing thaumasite sulfate attack (TSA) and enhancing ground limestone utilization in cement-ground limestone cementitious materials, this study examines the mechanisms underlying thaumasite formation and its relationship with temperature, cations, and ground limestone, utilizing thermodynamic principles. The findings indicate that thaumasite formation is constrained above 60.35 °C. Between 48.15 and 60.35 °C, only direct route is feasible, while below 48.15 °C, both direct and woodfordite routes occur spontaneously. As temperature decreases, Gibbs free energy changes decrease for both routes, promoting thaumasite formation. Mg2+ facilitates thaumasite formation via woodfordite route, while Na+ promotes it via direct route. With both Mg2+ and Na+ present, thaumasite formation depends on Na+ to Mg2+ ratio: below 5 favors woodfordite route, exceeding 5 favors direct route. Ground limestone reduces sulfate required for thaumasite formation, favoring the woodfordite route and exacerbating TSA; however, excessive ground limestone has a dilution effect on cement, thereby reducing thaumasite formation. [ABSTRACT FROM AUTHOR]

The in-situ reduction of zero-valent iron (ZVI) is an effective method for removing chlorinated aliphatic hydrocarbons (CAHs) from groundwater. The heterogeneity of environmental conditions is also crucial in affecting dechlorination efficiency. Until now, the effect of Sulfate (SO42–) on ZVI activity has been debated, and the related mechanism research on SO42– behaviour during the abiotic reduction process of chlorinated alkanes is still lacking. In this study, the impacts of SO42– concentrations (0, 2, 4, 8, 80 mM) on the degradation of 1,1,2-trichloroethane (1,1,2-TCA) by micron-size ZVI (mZVI) and nano-size ZVI (nZVI) were systematically investigated. For mZVI, Kobs increased by 0.6 (2 mM), 0.5 (4 mM), 1.1 (8 mM), and 1.6 times (80 mM). For nZVI, Kobs decreased by 32% (2 mM), 39% (4 mM), 45% (8 mM), and 9% (80 mM). The results showed that SO42– increased the rate of 1,1,2-TCA degradation by mZVI but weakened the reduction performance of nZVI; however, this inhibition was reduced when the concentration reached 80 mM. SO42− controlled the degradation of 1,1,2-TCA mainly through the formation of different iron-sulfate complexes on the ZVI surface: water-soluble bidentate iron-sulfate complexes formed on the mZVI surface promoted the corrosion of the oxide layer and accelerated the reduction of 1,1,2-TCA, monodentate complexes mainly formed on the nZVI surface inhibited the reduction of 1,1,2-TCA by blocking surface sites. These results demonstrate the proof of concept to assist land managers in the field application of ZVI technology for the remediation of CAHs contaminated sites with different background concentrations of SO42−. [ABSTRACT FROM AUTHOR]

A fast, simple and cost-effective technique has been used to produce spray-drying porous particles of salbutamol sulfate (SS) for inhalation drug delivery. The particles were produced using water as solvent and ammonium bicarbonate as pore-forming agent. A full factorial experimental design (24) with a central point was used to evaluate the influence of process parameters (drying air inlet temperature, atomization air volume flowrate, feed volume flowrate and the pore-forming agent concentration) on process yield, moisture content, densities and particle size. In addition, particle morphology, in-vitro aerosolization properties, stability and cytotoxicity of selected samples were studied. Within the experimental design parameters window, it was shown that the highest inlet temperature and pore-forming agent concentration were the factors that more affected the process yield and tap density values. Particles with the lowest tap densities values exhibited porous morphology. In addition, the pore-forming agent concentration proved to be the most significant variable affecting particle size. The highest pore-forming agent concentration, the largest particle size. The porous particles exhibit remarkable aerosolization performance, surpassing the performance of previously reported SS porous particles and a commercial formulation. These powders showed a high process yield and the absence of ammonium bicarbonate in the final product, as confirmed by FT-IR. Furthermore, the powders presented good stability even over long periods of time and did not exhibit cytotoxicity on the murine alveolar macrophage cell line RAW 264.7. [ABSTRACT FROM AUTHOR]