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The aim of this study was to investigate the efficacy of a surgical delay procedure and a combined surgical and chemical delay procedure on the survival of arterialized venous flaps. Experimental groups included (1) a control group, (2) a surgical delay (4-day and 7-day delay) group, and (3) a combined surgical and chemical (doxazosin mesylate, nitroglycerine patch) delay group. These groups were further divided into subgroups (n = 10) depending on the delay period and the chemical agents. An arterialized venous flap was created on one ear of each rabbit. In the arterialized venous flap, arterial inflow was provided by anastomosis of the central auricular artery to the anterior branch of the central auricular vein and a venous outflow through the anterior marginal vein. In the control group, the arterialized venous flaps without any delay procedure showed complete necrosis of all flaps. In the surgical delay group, the mean percentage survival of arterialized venous flaps was 36.6 percent in the 4-day delay group and 59.7 percent in the 7-day delay group. In the combined surgical and chemical delay group, a 3-day chemical delay followed by a 4-day simultaneous surgical and chemical delay resulted in mean percentage survival of the arterialized venous flaps of 81.1 percent in the doxazosin mesylate group, 72.8 percent in the nitroglycerine patch group, and 92.9 percent in a combination group of doxazosin mesylate and nitroglycerine patch. A 3-day chemical delay followed by a 7-day simultaneous surgical and chemical delay resulted in mean percentage survival of the arterialized venous flaps of 94 percent in the doxazosin mesylate group, 90.2 percent in the nitroglycerine patch group, and 99 percent in a combination group of doxazosin mesylate and nitroglycerine patch. In conclusion, the surgical delay procedure increased the percentage survival of the arterialized venous flaps in proportion to the delay period. The combination group of surgical and chemical delay procedures had a significantly greater percentage survival than that of the surgical delay group (p < 0.001), and the delay period could be shortened.

Plasma electrolytic oxidation (PEO) coatings were fabricated on 5083 Al alloy in KOH electrolyte solution with adding various concentrations of Na2SiO3. Changes in voltage–time response and micro-discharge evolution were analyzed, and the surface and cross-section of the resulting coating layer were further characterized by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD). The results showed that discharge characteristics were evidently changed with different Na2SiO3 concentrations, particularly higher Na2SiO3 concentrations leading to lower dielectric breakdown voltages. It was found that porous surface structure became prevalent with increasing Na2SiO3 concentration. The EDS analysis confirmed the incorporation of Si element in the PEO coatings. The result of XRD analysis revealed that metastable phases such as γ- and η-alumina were produced as a result of PEO, while amorphous phases appeared with excessive Na2SiO3 concentrations (10 and 14 g/L). The coating thickness was significantly increased about 2–8 times with increasing Na2SiO3, almost depending on Na2SiO3 concentration.

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