Air Pollutants, Occupational ; analysis ; Chromatography, Gas ; methods ; Fluorocarbon Polymers ; analysis ; Workplace

Electrochemical behaviors, electrochemical kinetics and electrochemical determination of sulfamethoxazole (SMZ) at both glassy carbon electrode (GCE) and multi-wall carbon nanotubes-Nafion modified glassy carbon electrode (MWCNTs-Nafion/GCE) were investigated by cyclic voltammetry (CV), chronocoulometry (CC), chronoamperometry (CA), linear scan voltammetry (LSV) and amperometric i-t curve. The experimental results showed that the electrochemical oxidation of SMZ was sluggish on GCE, but the oxidation peak current of SMZ increased significantly at MWCNTs-Nafion/GCE in comparison with that at the bare GCE, which indicated that MWCNTs-Nafion/GCE could catalyze the electrochemical oxidation of SMZ very well. The plot of oxidation peak currents versus the square roots of the scanning rates for the redox in the potential range of 10-1,000 mV x s(-1) showed a straight line, as expected for a diffusion-limited electrochemical process for SMZ electrochemical oxidation. At the bare GCE and MWCNTs-Nafion/GCE the oxidation peak current was linearly proportional to the concentration of SMZ over the concentration range 5.0 x 10(-5)-2.5 x 10(-3) mol x L(-1) and 1.0 x 10(-5)-6.0 x 10(-3) mol x L(-1). The detection limits were 1.0 x 10(-5) and 5.0 x 10(-7) mol x L(-1). The relative standard deviation was between 0.85% -1.98% and the recovery was in the range of 98%-101.2%. This MWCNTs-Nafion/GCE could be applied in SMZ electrochemical determination with satisfied results. The proposed method can be applied to the determination of SMZ in tablet samples with satisfied results.
Catalysis ; Electrochemistry ; methods ; Electrodes ; Fluorocarbon Polymers ; chemistry ; Kinetics ; Nanotubes, Carbon ; Oxidation-Reduction ; Sulfamethoxazole ; analysis ; chemistry

Objective: This study evaluated the functional and cosmetic outcomes after bilateral frontalis sling repair using either expanded polytetrafluoroethylene (ePTFE) or silicone rod for unilateral or bilateral severe congenital ptosis with poor levator function. Methods: This was a non-comparative, interventional case series involving 30 patients with unilateral or bilateral severe congenital ptosis who underwent bilateral frontalis sling repair from February 2012 to November 2018. Medical records including pre- and postoperative photographs were reviewed. The functional and cosmetic outcomes were assessed. Results: There were 15 patients with severe congenital ptosis who underwent ePTFE surgery and 15 patients who had silicone rod surgery. Baseline levator function measured was less than 5 mm in all patients. The mean follow-up duration after surgery was 15.6+6.9 months. Satisfactory eyelid contour was observed in all patients (100%). Postoperatively, all had good to excellent primary eyelid position and effective frontalis action on eyelid elevation. Complications included exposure of the silicone sling material after trauma at the brow area (n=1) and recurrence of ptosis (n=2). Conclusion Bilateral frontalis suspension in patients with severe congenital ptosis, whether bilateral or unilateral, resulted in excellent functional and cosmetic outcomes using ePTFE or silicone rod.
Polytetrafluoroethylene

No abstract available.
Mandible ; Osteogenesis ; Proplast

PURPOSE: The purpose of this study is finding proper bonding agents to be used when adding bis-acryl composite provisional materials. MATERIALS AND METHODS: Three bonding agents with different chemical compositions were included in this study. Forty disk shaped specimens of bis-acryl composite provisional material were prepared and divided into 4 groups according to the bonding agents. Control group didn't have bonding agent. Through the Teflon mould with 4.0 mm diameter hole with 4.0 mm thickness the same bis-acryl composite provisional material was added on the disks after the surface of each specimen was treated with designated bonding agent according to the manufacturer's instructions. Shear bond test was performed and the fractured surfaces were inspected with a microscope. One-way analysis of variance was conducted and the result was further analysed with Turkey post hoc test at the significance level of 0.05. RESULTS: The highest strength was acquired from the specimens bonded with chemical cure system and it was statistically significant (P < 0.05). This group showed 100% cohesive failures. The lowest bonding strength was recorded from the specimens used conventional light cure bonding agent, and this group's result was similar with the control group. The group used a light cure bonding agent claiming improved compatibility revealed significantly higher bond strength to the traditional light cure bonding agent group in a statistically significant way (P = 0.043). CONCLUSION: According to the bonding agent used the shear bond strength was significantly affected. Therefore the choice of proper bonding agent is important when hiring a bonding agent to add bis-acryl composite provisional materials.
Polytetrafluoroethylene ; Turkey

No abstract available.
Membranes* ; Polytetrafluoroethylene*

No abstract available.
Ligaments* ; Polytetrafluoroethylene*

In order to prevent the formation of postoperative adhesions and delay the time of adjustment, the authors tried 5-fluorouracil and physical barriers of polytetrafluoroethylene, Interceed, Viscoat in rabbits. Fluorouracil delayed the adjustment for up to one week after surgery in three out of four eyes. Combined use of Interceed and 5-fluorouracil of addition of Viscoat could delay the adjustment for up to two weeks after surgery I one out of four eyes. Combined use of pophtetrafluoroethylene and 5-fluorouracil of addition of Viscoat could delay the adjustment for up to four weeks after surgery in four out of five eyes. In conclusion, combined use of polytetrafluoroethylene, 5-fluorouracil and Viscoat could be more helpful for delayine adjustment in rabbits.
Fluorouracil* ; Polytetrafluoroethylene ; Rabbits ; Strabismus*

Delayed reattachment of the muscle to the sclera may be desirable to correct the deviation of eye developed after the surgery. Polytetrafluoroethylene(PTFE) was placed around the cut end of the muscle as a physical barrier between the free muscle end and the sclera in 16 rabbits in order to prevent the postoperative adhesions. PTFE was effective in delaying the adjustment for up to 4 weeks after surgery in 4 out of 10 eyes. After removal of PTFE, adjustment was possible up to 12 weeks in 24 out of 25 eyes because there was no adhesion between the muscle and PTFE. In conclusion, PTFE may be clinically helpful for delaying the timing of adjustment.
Polytetrafluoroethylene* ; Rabbits ; Sclera ; Strabismus*

BACKGROUND: Gore-Tex implants started out as a product with the distinct advantage of producing a natural nose shape, but using Gore-Tex, it is difficult to predict the height of the nose after rhinoplasty because Gore-Tex contracts over time, making the nose shrink. However, Surgiform, a new form of expanded polytetrafluoroethylene (ePTFE) implant, enables prediction of the height of the nose after rhinoplasty because the implant does not change in thickness even after many years. Thus, we investigated whether changes in implant thickness occurred after rhinoplasty using Surgiform implants. METHODS: This study enrolled 12 patients who had Surgiform nasal implants removed for any reason after receiving rhinoplasty in 2007 or later. After the Surgiform implants were removed, we measured the thickness of the central part of the implants using calipers. RESULTS: At the time of the initial operation, the mean implant thickness was 4.48±0.30 mm at the supra-tip. At the time of implant removal, the mean thickness was 4.32±0.29 mm. The implants maintained 96.5% of their initial thickness. There was a negligible reduction in the Surgiform implants' thickness over time. CONCLUSIONS: Surgiform implants maintained their shape after rhinoplasty, making it possible to predict the height of the nose. Thus, Surgiform is more useful for nasal implants than other ePTFE implants.
Humans ; Nose ; Polytetrafluoroethylene ; Rhinoplasty