Effect of Treatment with Microarc Oxidation Technology on Tribological Properties of Nonvalve Metal Low-Carbon Steel

Steel is one of the most widely used alloys because of its excellent properties such as high toughness, good workability, and low cost. However, steel has weak wear resistance, which limits its range of applications and service life. We have used the microarc oxidation (MAO) technique to form an Al2O3 ceramic coating on the surface of nonvalve metal low-carbon steel, which is used to enhance the wear resistance of low-carbon steel. Tribological experiments have shown that the coefficient of friction is reduced by 26.9%, hardness is improved, and wear resistance is enhanced after MAO compared to the substrate. Through a series of characterizations, the wear mechanism of the MAO samples was found to be a complex friction mechanism including abrasive wear, adhesive wear, and friction oxidation. After MAO, the wear resistance of nonvalve metal low-carbon steel is improved. The use of steel can be extended and its service life can be prolonged. This innovative approach provides a viable solution for the development of low-carbon steel coatings.

Carbon-coated selenium nanoparticles for photothermal therapy in choriocarcinoma cells

Choriocarcinoma can be cured by chemotherapy, but this causes resistance and severe side effects that bring about physical and psychological consequences for patients. Therefore, there is still an urgent need to find other alternative minimally invasive therapies to halt the progression of choriocarcinoma. Novel carbon-coated selenium nanoparticles (C-Se) were successfully synthesized for choriocarcinoma photothermal therapy. C-Se combined with near-infrared laser irradiation can inhibit the proliferation of human choriocarcinoma (JEG-3) cells and induce cell apoptosis. C-Se killed cells and produced ROS under near-infrared laser irradiation. Finally, the therapeutic mechanism of C-Se + laser was explored showing that C-Se + laser influenced numerous biological processes. Taken together, C-Se exhibited significant potential for choriocarcinoma photothermal therapy.

Preparation and characterization of polyethylene glycol/chitosan composite water-based wound healing lubricant

The proportion of pregnant women giving birth through cesarean section is increasing annually worldwide. However, post-cesarean section scar diverticulum is a common condition that occurs and requires better surgical strategies than the methods currently used. We hypothesized that using biological lubricant topically on the incision area during C-section could be an option to minimize the scar. This water-based polyethylene glycol (PEG)/chitosan (CS) composite lubricant was prepared via ultrasonic blending. The product was characterized using scanning electron microscopy, X-ray photoelectron spectroscopy, X-ray diffraction, Fourier-transform infrared spectroscopy, and Raman spectroscopy. The thermal stability of the materials and their heat absorption and release during heating were analyzed using thermogravimetric analysis and differential scanning calorimetry. Tribological tests proved that the PEG/CS composite had a better lubrication effect than either the PEG or CS lubricant alone, and the cell viability experiments verified that it had good biocompatibility. Finally, application of the composite lubricant onto the backs of mice modeling full-thickness skin incisions further confirmed that the product improved both the re-epithelialization and the collagen levels of the wounded skin. In conclusion, we expect our newly formulated PEG/CS composite lubricant to be useful not only for managing post-cesarean section scar diverticulum but also for healing skin wounds in general.