RESUMEN
Waste cooking oils (WCOs) show promise as a rejuvenator for reclaimed asphalt pavement (RAP) binders. Their use helps to make RAP a renewable resource and to address environmental concerns related to WCO disposal. While studies suggest that 100% RAP for pavement is feasible, RAP will likely be combined with a virgin binder and aggregate incrementally in the field. In this study, the rheological properties of the virgin binder blended with a simulated RAP binder and 10% waste vegetable oil (WVO) as a rejuvenator were examined. Viscosities below that of a PG 64-22 virgin binder were observed with WVO in blends of 40 or 60% RAP and the virgin binder. The virgin-60% RAP/WVO binder blend retained a Superpave grade of the virgin binder and was found to satisfy requirements for both rutting parameter and fatigue resistance. Results indicated that WVO significantly reduced the effects of long-term ageing, making the blend containing RAP durable. The effect of RAP content on WVO/virgin binder blends was most pronounced on the rutting parameter. A "molecular lubrication" model is suggested as a mechanism for the viscosity reduction with WVO.
RESUMEN
PRéCIS:: Intracameral injection of viscoelastic at the beginning of Ahmed FP7 implantation did not reduce early postoperative complication rates. PURPOSE: To evaluate early postoperative complication rates after a modified technique in which the anterior chamber (AC) is filled with viscoelastic at the beginning of Ahmed FP7 implantation before conjunctival peritomy. SUBJECTS AND METHODS: A retrospective chart review was performed of eyes that underwent Ahmed FP7 implantation with or without viscoelastic fill to ~20 mm Hg by finger tension by a single surgeon (M.R.M). Viscoelastic prevented the AC from becoming shallow at any time during surgery, and additional viscoelastic was injected into the AC at the end of surgery to achieve a final intraocular pressure (IOP) of 20 mm Hg. RESULTS: A total of 159 eyes of 159 patients were included. Mean age was 76.4±10.4 years. Mean preoperative IOP was 30.3±9.7 mm Hg on 2.7±1.2 glaucoma medications. On postoperative day 1, there was an IOP spike ≥30 mm Hg in 0% of patients. Within the first postoperative month, hypotony (<5 mm Hg) occurred in 19 (21.8%) eyes that received viscoelastic fill compared with 5 (13.2%) eyes that did not receive viscoelastic fill (P=0.26). During the early postoperative period (≤3 mo), there was no difference in AC depth, microhyphema, choroidal effusion, or leakage between the 2 groups (P≥0.30 for all). There was a higher rate of layered hyphemas in the viscoelastic-fill group at postoperative week 1 (P=0.01). At 3-month follow-up, mean IOP was 14.9±5.5 mm Hg on 1.6±0.8 medications in the viscoelastic-fill group and 16.0±5.2 mm Hg on 1.0±1.2 medications in the nonviscoelastic-fill group (IOP P=0.35). Compared with baseline, change in IOP at 3 months was similar between both groups (P=0.15). Rates of additional medications and procedures did not differ between the 2 groups at any postoperative visit. CONCLUSIONS: Early intracameral injection of viscoelastic during Ahmed glaucoma valve implantation did not reduce early postoperative complication rates.
