Preparation of magnetic biochar and its catalytic role in degradation of Cu-EDTA by heterogeneous Fenton reaction.

In this study, magnetic biochar (Fe-BC) was synthesized from phoenix tree leaves and FeSO4·7H2O by impregnation-pyrolysis method, and was used to activate H2O2 to degrade Cu-EDTA. The effects of preparation parameters on the degradation of Cu-EDTA by Fe-BC/H2O2 system were investigated by degradation experiments and characterization methods (SEM, BET, FTIR, XRD and XPS). The results showed that the magnetic biochar prepared under the pyrolysis temperature of 400 °C, pyrolysis time of 3 h and iron content of 3 wt% had the best catalytic activity. Within 120 min, the breaking efficiency of Cu-EDTA binding, precipitation efficiency of Cu2+ and removal efficiency of TOC could reach 78.48, 71.65 and 46.54% at the conditions of adding 1.0 g/L magnetic biochar and 25 mM H2O2 and the iron dissolution was only 0.32 mg/L. The characterization results and comparison experiments demonstrated that the catalytic effect of magnetic biochar not only depends on the transfer of electrons to H2O2 by the loaded iron oxides, but also the active oxygen functional groups (OFGs) and persistent free radicals (PFRs) contained on the surface can transfer electrons to H2O2 or even dissolved oxygen to produce an amount of hydroxyl radicals (·OH) and superoxide anion radicals (O2·-).

Repair of Compound Dorsal Defects of the Digits Using a Free Antegrade Palmaris Longus Tendocutaneous Venous Flap.

PURPOSE: To investigate the clinical effect of repairing small dorsal digit compound tissue defects using a free palmaris longus tendocutaneous flap nourished by venous blood. METHODS: In a retrospective analysis of patients treated between March 2010 and October 2017, 18 patients were identified as having small compound tissue defects, which were repaired using a free palmaris longus tendocutaneous flap nourished by venous blood. The average age of the patients, including 15 male and 3 female patients, was 34 years (range, 22-55 years). The mean wound size was 6 cm2 (range, 2.0 × 1.5 to 3.5 × 2.0 cm2). All the patients had dorsal defects. The average length of extensor tendon defect was 2.0 cm (range, 1.0-3.0 cm). The mean area of the flap was 7 cm2 (range, 2.5 × 2.0 to 4.0 × 3.5 cm2). The donor sites were primarily closed. RESULTS: All 18 flaps survived. A vascular crisis due to a venospasm occurred within 48 hours in 3 flaps, but ultimately, all the flaps survived. The patients were followed-up for a mean period of 10 months (range, 3-15 months). All the patients returned to their previous work after 10-12 weeks. No pain or scar contracture was reported in either the recipient or donor site. CONCLUSIONS: The free antegrade palmaris longus tendocutaneous venous flap enabled the repair of compound tissue defects of the dorsal digit, resulting in acceptable aesthetics, repaired tendon defects, and wound coverage. This surgical method is an option for the reconstruction of small compound defects of digits with extensor defects. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.