• Title/Summary/Keyword: SCAR

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Synthesis and Lubrication Properties of Semi-Fluorinated Polyol Esters (불소계 폴리올에스테르의 합성과 윤활 특성)

  • 백진욱;정근우;김영운
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • 2001.06a
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    • pp.149-155
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    • 2001
  • New semi-fluorinated polyol esters were synthesized by condensation reaction of polyols (NPG and TMP) and carboxylic acids such as 2-ethylhexanoic acid, stearic acid and perfluorooctanoic acid. The structures of polyol esters were confirmed by FT-IR and H-NMR etc. And, the fluorinated polyol esters were insoluble in several oils, however, the semi-fluorinated polyol esters were soluble in several oils depended on the structure of polyol esters. The physical properties such as 4-ball wear property and extreme-pressure (EP) properties were characterized by measuring wear scar diameter through ASTM D2266 and by determining the load-carrying through ASTM D2783 method, respectively. As the results, wear scar diameters of oils in which the semi-fluorinated polyol esters were added were not changed compared to those of not added oils. While extreme-pressure properties remarkably Increased with fluorine contents of the esters depended on the structure of acid moiety and polyol moiety. Also, the extreme-pressure property of semi-fluorinated NPG polyol ester in gasoline engine oil was better than that of commercial Teflon coating additive.

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Correction of pixie ear: infraauricular skin redraping method

  • Kim, Jun Hyeok;Yang, Young Bin;Oh, Deuk Young
    • Archives of Craniofacial Surgery
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    • v.23 no.4
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    • pp.187-189
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    • 2022
  • Patients with pixie ear have an attached, tapering, and low-set earlobe. Traditional methods usually describe excision of the caudal portion of the lobule and reattachment in a more superior position. The present report suggests a simplified skin redraping method for correction of pixie ear. The procedure provides easy method to design and perform, which only requires elevation and trimming of the skin. Other ancillary procedures, such as flap design, anchoring, plication, and subdermal fixation, are not required. This method produces satisfactory results. Postoperative scar is invisible because the incision is on the retroauricular region, and the corrected earlobe has a more natural appearance than the repositioned earlobe. Moreover, skin redraping avoids tension, which contributes to minimization of the postoperative scar.

Successful Treatment of Post-operative Keloid with Combined Cryotherapy and Ablative Fractional CO2 Laser

  • Kim, Jihee;Lee, Young In;Lee, Ju Hee;Oh, Sang Ho;Lee, Sang Eun;Kim, Young Koo
    • Medical Lasers
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    • v.9 no.1
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    • pp.58-61
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    • 2020
  • Keloids are pathologic fibroproliferative conditions characterized by excessive collagen deposition during wound healing. The pathogenesis of keloids is not fully understood, and current treatment options show variable results. In this case report, the patient developed a keloid after bilateral total thyroidectomy, and was treated with a combination approach using fractional ablative laser systems along with cryotherapy and triamcinolone injection. After seven monthly sessions of combination treatment, the patient presented marked improvement of the scar texture and symptoms. Furthermore, there was no recurrence for up to 2 years. We propose this combination as a safe and effective treatment option for keloid patients.

Reciprocating Wear Test of AISI 52100 Bearing Steel in h-BN-based Aqueous Lubricants

  • Gowtham Balasubramaniam;Dae-Hyun Cho
    • Tribology and Lubricants
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    • v.39 no.6
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    • pp.228-234
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    • 2023
  • In this study, reciprocating wear tests are performed on AISI 52100 bearing steel to investigate its tribological behavior in a hexagonal boron nitride (h-BN) water solution. The h-BN-based aqueous lubricant is prepared using an atoxic procedure called ultrasonic sonication in pure water. Ball-on-flat reciprocating sliding experiments are conducted, where the ball is slewed on a fixed flat at 50-㎛ displacement. The lubricating behavior of h-BN is compared with that of deionized (DI) water. Results show that the friction coefficient is higher in h-BN testing than that in DI tests, but the results are equalized as the friction coefficient reaches a stable level. Scanning electron microscopic images reveal significant material loss in the center and mild abrasion on the edge of the wear scar in h-BN tests. However, these effects are minor in DI water situations. The results of energy-dispersive X-ray spectroscopy show that considerable oxidation occurs in the central zone of the wear scar in h-BN cases with strong adhesion and material removal. These findings reveal the importance of determining ideal circumstances that can tolerate material friction and wear.

The Square-Plus Flap: A Modification to Release Long Postburn Scar Contractures

  • Mahmoud A. Hifny;Rei Ogawa
    • Archives of Plastic Surgery
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    • v.51 no.1
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    • pp.126-129
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    • 2024
  • The square flap method has been successful in releasing contracture bands at various body regions. However, the original square flap method alone may not be efficient in releasing long contracture bands. We, therefore, proposed an extended design to the traditional design, which is called the "square-plus flap." A 4-year-old girl presented with a postburn web-like contracture band over the right axilla. We marked a square flap technique at the center of the contracture band and then two additional Z-plasties were placed on both edges of the flap. After the release and securing of the square flap, the adjacent distal Z-plasty was then transposed and sutured in their new locations. We do not need to incise the proximal Z-plasty as we could achieve complete relaxation of the contracture band. This novel modification can be added to the plastic surgeon's armamentarium for releasing long postburn contracture bands involving distinct body regions.