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The chloride content is a critical factor influencing the corrosion of steel fibers in concrete. This study focused on the corrosion behaviors of steel fibers exposed to simulated concrete pore solutions with different chloride contents. The corrosion rates of the steel fibers were calculated based on the changes in the diameter and ultimate tensile load. The electrochemical parameters for the corrosion of the steel fibers were continuously monitored for 62 days. In addition, the surface micromorphologies of the corroded steel fibers were observed using scanning electron microscopy (SEM). The results showed that based on the change in the diameter, the corrosion rate of the steel fibers increased almost linearly when the NaCl content in the simulated solution increased from 2% to 5%. However, based on the variation of the ultimate tensile load, the corrosion ratio of the steel fibers increased linearly with the increase in the exposure time when the NaCl content was less than 3%, while it increased exponentially when the NaCl content exceeded 3%. According to the open circuit potential, Tafel polarization curves, and electrochemical impedance spectroscopy (EIS), the corrosion tendency and corrosion rates of the steel fibers exposed to the simulated solutions increased significantly when the NaCl content increased from 2% to 5%. Additionally, the corrosion damage on the surfaces of the steel fibers increased notably, and after 180 days of exposure to the simulated solution with 5% NaCl, the steel fiber was almost broken. These findings will help to understand the durability of SFRC in a chloride environment. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the chiral inversion and the stereoselective pharmacokinetic profiles of desmethyl‐phencynonate hydrochloride after administration of the single isomer and its racemate to beagle dogs. A liquid chromatography with tandem mass spectrometry (LC–MS/MS) method was established for determination of the stereoisomers on chiral columns in beagle dog plasma, which met all the requirements. The chiral inversion in dogs of the desmethyl‐phencynonate hydrochloride were studied after administration of the single isomer or the racemic modification. The stereoselective pharmacokinetic profiles of the desmethyl‐phencynonate hydrochloride were studied by assays for simultaneous isomers after administration of the racemic modification. The results showed that the absorption of the R-configuration dosed as the single isomer was higher than it dosed as the racemic modification. The AUC(0‐t), AUC(0‐∞), and Cmax of the S-configuration were much higher than those of R-configuration after oral administration of the racemic desmethyl‐phencynonate hydrochloride. The chiral inversion of desmethyl‐phencynonate isomers could not occur in dogs after administration of the R-configuration. [ABSTRACT FROM AUTHOR]

As an essential nutrient, lutein (LUT) has the ability to aid in the prevention of eye diseases, cardiovascular diseases, and cancer. However, the application of LUT is largely restricted by its poor solubility and susceptibility to oxidative degradation. Thus, in this study, LUT-loaded nanogel (OVM-COS-LUT) was prepared by a self-assembly of ovomucin (OVM) and chitosan oligosaccharide (COS) to enhance the effective protection and bioavailability of LUT. The nanogel had excellent dispersion (PDI = 0.25) and an 89.96% LUT encapsulation rate. XRD crystal structure analysis confirmed that the encapsulated LUT maintained an amorphous morphology. In addition, the nanogel showed satisfactory stability with pH levels ranging from 2 to 9 and high ionic strengths (>100 mM). Even under long-term storage, the nanogel maintained an optimistic stabilization and protection capacity; its effective retention rates could reach 96.54%. In vitro, digestion simulation showed that the bioaccessibility and sustained release of OVM-COS-LUT nanogel was superior to that of free LUT. The nanogel provided significant antioxidant activity, and no significant harmful effects were detected in cytotoxicity analyses at higher concentrations. In summary, OVM-COS-LUT can be utilized as a potential safe oral and functional carrier for encapsulating LUT. [ABSTRACT FROM AUTHOR]

This study investigated the effect of alkalis on C3S hydration with and without incorporating aluminate phases. Pastes of 100% C3S and 90% C3S+10% metakaolin (MK) were prepared at 1%, 2%, and 3% Na2O content. X-ray diffraction (XRD) and thermogravimetric analysis (TGA) were used to characterize the solid phase assemblages, and then the hydration degree of C3S. Inductively coupled plasma optical emission spectroscopy (ICP-OES) was used to analyze the aqueous composition of pore solution. Mercury intrusion porosimetry (MIP) was used to measure the porosity of the hydrated pastes. The results highlighted the promoting effect of Na and the inhibiting effect of Al in pore solution on C3S hydration after a period of curing (90 days). Without incorporating metakaolin, the hydration degree of C3S continuously increased with the increase of Na concentration. Incorporating metakaolin into C3S can generate aluminate hydrates (carboaluminates, in this study), and the increased Na concentration can increase the dissolution or instability of carboaluminates and elevate the equilibrium Al concentration. Under this condition, the hydration degree of C3S fluctuated depending on the combined effect of Na and Al concentrations in pore solution on C3S hydration. [ABSTRACT FROM AUTHOR]

In this study, 37 derivatives of phorbol esters were synthesized and their anti-HIV-1 activities evaluated, building upon our previous synthesis of 51 phorbol derivatives. 12-Para-electron-acceptor- trans -cinnamoyl-13-decanoyl phorbol derivatives stood out, demonstrating remarkable anti-HIV-1 activities and inhibitory effects on syncytia formation. These derivatives exhibited a higher safety index compared with the positive control drug. Among them, 12-(trans -4-fluorocinnamoyl)-13-decanoyl phorbol, designated as compound 3c , exhibited the most potent anti-HIV-1 activity (EC 50 2.9 nmol·L−1, CC 50 /EC 50 11 117.24) and significantly inhibited the formation of syncytium (EC 50 7.0 nmol·L−1, CC 50 /EC 50 4891.43). Moreover, compound 3c is hypothesized to act both as an HIV-1 entry inhibitor and as an HIV-1 reverse transcriptase inhibitor. Isothermal titration calorimetry and molecular docking studies indicated that compound 3c may also function as a natural activator of protein kinase C (PKC). Therefore, compound 3c emerges as a potential candidate for developing new anti-HIV drugs. [ABSTRACT FROM AUTHOR]

Morroniside is one of the most important iridoid glycosides from Cornus officinalis Sieb. et Zucc. In the present study, the pharmacokinetics and bioavailability studies of morroniside were conducted on Sprague-Dawley (SD) rats. A rat in situ intestinal perfusion model was used to characterize the absorption of morroniside. Caco-2 cells were used to examine the transport mechanisms of morroniside. The pharmacokinetic study of morroniside exhibited linear dose-proportional pharmacokinetic characteristics and low bioavailability (4.3 %) in SD rats. Its average Peff value for transport across the small intestinal segments changed from (3.09 ± 2.03) × 10−6 to (4.53 ± 0.94) × 10−6 cm s−1. In Caco-2 cells, the Papp values ranged from (1.61 ± 0.53) × 10−9 to (1.19 ± 0.22) × 10−7 cm s−1 for the apical to basolateral side and the Pratio values at three concentrations were all lower than 1.2. Morroniside showed poor absorption and it might not be a specific substrate of P-glycoprotein (P-gp).