Preparation of healing-promoting and fibrosis-inhibiting asymmetric poly(ethylene glycol-b-L-phenylalanine)/cRGD-modified hyaluronate sponges and their applications in hemorrhage and nasal mucosa repair.

Acute or chromic bleeding, such as epistaxis, requires hemostatic materials to assist hemostasis. Even in complex cases, hemostatic materials must have other functions, including the promotion of healing and prevention of adhesion. Herein, a series of fibrosis-suppressive functional cRGD-modified crosslinking hyaluronic acid sponges were prepared. The in vitro hemostatic efficiency and mechanism were determined using blood clotting time, blood coagulation index, lactate dehydrogenase (LDH) and thromboxane B2 (TX-B2) ELISA, and proteomics. Among the prepared sponges, both poly(ethylene-b-L-Phe) (PEBP)-and cRGD contained SPN4 and exhibited the highest platelet concentration and activation efficiency as well as the most effective coagulative effect. In addition, no significant cytotoxicity was observed for the sponges in rat airway epithelial cells. The in vivo hemostatic and adhesion-preventive effects of the sponges were evaluated using rat models of liver injury and sidewall defect-cecum abrasion. PEBP-containing sponges effectively prevented postoperative adhesion and cRGD-modified sponges exhibited excellent hemostatic effects. Finally, the comprehensive repair effects of the sponges were evaluated using a rabbit maxillary sinus mucosal injury model, based on CT, MRI examination, and pathological staining. SPN4 exhibited the best comprehensive reparative effects, including the promotion of mucosal repair and infection inhibition. Thus, SPN4 is a promising multifunctional hemostatic material.

Efficacy of positive space acquiring membrane and antimicrobial membrane combined with granular bone substitute implantation in guiding oral bone regeneration.

Augmentation of the alveolar bone is important before oral implantation. For large bone defects, it becomes necessary to apply guided bone regeneration (GBR) materials, accompanied by filling defect sites with autologous or allogeneic bone, or bone substitutes such as acellular bone powder. In this study, we tested a granular bone substitute and GBR membrane combination therapy in treating MC3T3-E1 and L929 cells in vitro and rat calvarial and alveolar defects in vivo. The recovery conditions of bone defects were monitored by micro-CT, and 3D reconstruction of the CT images was applied to evaluate the bone augmentation semi-quantitatively. Test GBR materials could support the proliferation of MC3T3-E1 cells, poly (p-dioxanone-co-L-phenylalanine) (PDPA)-based membrane could induce apoptosis of L929 cells. Among GBR membranes applied groups, the regeneration condition of defected calvarial defects of PDPA based membrane applied group was the best and this may be caused by its excellent positive space acquiring effect. However, in a complex bacteriogenic environment, the oral bone regeneration-guided efficacy of the PDPA membrane decreased in the post-repair stage with the aggravation of infections. By contrast, the antimicrobial membrane combined with the PDPA membrane exhibited continually increasing GBR efficacy at the later stage of repair owing to its multifunctional properties, which are infection-inhibiting and positive space acquiring. Therefore, multifunctional GBR membranes are preferable for GBR in complex oral environments, and further research should be conducted to determine their efficacy in other models.

Relations between Prosociality and Psychological Maladjustment in Chinese Elementary and Secondary School Students: Mediating Roles of Peer Preference and Self-Perceived Social Competence.

Despite empirical findings that prosociality can prevent elementary and secondary school students from developing psychological maladjustment, little is known about the underlying mechanisms. The goal of the present study was to examine the mediating effects of peer preference and self-perceived social competence on the associations between prosociality and psychological maladjustment (i.e., depressive symptoms and loneliness). Participants were 951 students (Mage = 11 years, 442 girls) in Grades 3~7 from Shanghai, China. They completed peer nominations of prosociality and peer preference and self-report measures of self-perceived social competence, depressive symptoms, and loneliness. Multiple mediation analyses revealed that: (a) both peer preference and self-perceived social competence mediated the relations between prosociality and psychological maladjustment, and (b) a serial indirect pathway (i.e., prosociality → peer preference → self-perceived social competence → psychological maladjustment) emerged when controlling for age group and gender. These findings point to potential targets in the prevention and intervention of Chinese students' internalization of problems.

Preparation and in vivo bacteriostatic application of PPDO-coated Ag loading TiO2 nanoparticles.

Implant-associated infections limit the clinical application of implants therapy; hence, exploiting strategies to prevent biomaterial-associated infections has become important. Therefore, in this study, a series of poly (p-dioxanone) (PPDO)-coated Ag loading TiO2 nanoparticles (Ag@TiO2-PPDO) was synthesized to be applied as bacteriostatic coating materials that could be easily dispersed in organic solvent and coated onto implantable devices via temperate methods such as electrospraying. The lattice parameters of TiO2 were a = 0.504 nm, b = c = 1.05 nm, alpha = beta = gamma = 90 degree and the size of crystallite was about 13 nm, indicating that part of Ag has been embedded into crystal defects of TiO2. Both XRD and TEM determinations indicated the successful grating of PPDO on the surface of Ag@TiO2. Among Ag@TiO2 nanoparticles with various Ag loading quantities, 12% Ag@TiO2 nanoparticles exhibited relatively higher grafting efficiency and Ag contents on the surface of grafted composites. In addition, 12% Ag@TiO2-PPDO exhibited the best bacteriostatic effect in vitro owing to its higher grafted efficiency and relatively short length of PPDO segments. Subsequently, Ag@TiO2-PPDO was coated on the surface of a poly lactic-co-glycolic acid (PLGA) electrospun membrane via the electrospraying method. Finally, the in vivo bacteriostatic effect of 12% Ag@TiO2-PPDO coating was verified by implanting 12% Ag@TiO2-PPDO-coated PLGA membrane into a rat subcutaneously combined with an injection of Staphylococcus aureus at implanting sites.

Synthesis of α-Fe2O3 nanofibers for applications in removal and recovery of Cr(VI) from wastewater.

PURPOSE: Nanomaterials such as iron oxides and ferrites have been intensively investigated for water treatment and environmental remediation applications. The purpose of this work is to synthesize α-Fe(2)O(3) nanofibers for potential applications in removal and recovery of noxious Cr(VI) from wastewater. METHODS: α-Fe(2)O(3) nanofibers were synthesized via a simple hydrothermal route followed by calcination. The crystallographic structure and the morphology of the as-prepared α-Fe(2)O(3) nanofibers were characterized by X-ray diffraction, scanning electron microscope, and transmission electron microscope. Batch adsorption experiments were conducted, and Fourier transform infrared spectra were recorded before and after adsorption to investigate the Cr(VI) removal performance and adsorption mechanism. Langmuir and Freundlich modes were employed to analyze the adsorption behavior of Cr(VI) on the α-Fe(2)O(3) nanofibers. RESULTS: Very thin and porous α-Fe(2)O(3) nanofibers have been successfully synthesized for investigation of Cr(VI) removal capability from synthetic wastewater. Batch experiments revealed that the as-prepared α-Fe(2)O(3) nanofibers exhibited excellent Cr(VI) removal performance with a maximum adsorption capacity of 16.17 mg g(-1). Furthermore, the adsorption capacity almost kept unchanged after recycling and reusing. The Cr(VI) adsorption process was found to follow the pseudo-second-order kinetics model, and the corresponding thermodynamic parameters ΔG°, ΔH°, and ΔS° at 298 K were calculated to be -26.60 kJ mol(-1), -3.32 kJ mol(-1), and 78.12 J mol(-1) K(-1), respectively. CONCLUSIONS: The as-prepared α-Fe(2)O(3) nanofibers can be utilized as efficient low-cost nano-absorbents for removal and recovery of Cr(VI) from wastewater.