Nasal ala V-Y island flap with a superior vascular pedicle based on inferior perforators of the superior alar artery.

For small defects of the anterior nasal ala, a V-Y pedicle advancement flap within the subunit is a useful repair option. Here we propose a modification of this technique, utilising careful dissection to identify inferior perforators of the superior alar artery. Basing this flap on a visualised vascular pedicle aims to prevent common complications of internal mucosal buckling and free margin notching, by allowing more extensive dissection without compromising the vascularity of the flap.

Efficacy of secondary intention healing for scalp defects-Case series from a single institution.

BACKGROUND/OBJECTIVES: As surgical techniques evolve, there remains underutilisation of secondary intention healing as a valid reconstruction option. This is largely due to concerns regarding inferiority of wound cosmesis, increased downtime with wound healing and infection risk (Dermatol Surg. 2020; 46(12): 1492-97). METHODS: We sought to look at the outcome of secondary intention healing in a cohort of patients seen at a private dermatology practice with small to medium sized scalp defects. All patients completed a satisfaction survey that further evaluated its feasibility. RESULTS: Excellent cosmetic outcome was noted with secondary intention healing for small to medium scalp defects, specifically in patients with thinning scalps that allowed healing without patchy alopecia. CONCLUSIONS: Secondary intention healing should be considered as a reconstructive option for scalp defects, especially in the right patient cohort.

Effects of stretch and thermal radiation on difluoromethane/air burning velocity measurements in constant volume spherically expanding flames.

Compared to current refrigerants, next-generation refrigerants are more environmentally benign but more flammable. The laminar burning velocity is being used by industry as a metric to screen refrigerants for fire risk, and it is also used for kinetic model development and validation. This study reports measurements of difluoromethane/air flame burning velocities for equivalence ratios from 0.9 to 1.4 in a spherical, constant volume device. Experimental burning velocities produced with the aid of an optically thin radiation model are about 17 % greater than those obtained with an adiabatic model. Characterization of flame stretch based on the product of Markstein and Karlovitz numbers indicates that while many experimental data are nearly stretch-free, those for slower burning velocities, smaller flame radii, and leaner conditions may not be. Limiting the data to regions estimated to be stretch-free requires extrapolation away from the experimental conditions to extract burning velocities near ambient conditions, e.g., at (298 K, 101 kPa). Lower uncertainty, desirable for kinetic model validation, is obtained by interpolating between experimental conditions, e.g., at (400 K, 304 kPa). Since thermal radiation and flame stretch were found to affect the inferred burning velocities of difluoromethane/air constant volume spherical flames, they should also be considered during data reduction of other mildly flammable refrigerants.

Perineural invasion present exclusively in central tissue blocks of Mohs surgical excisions of basal cell carcinoma.

Perineural invasion (PNI) may be present in basal cell carcinomas (BCC) treated with Mohs micrographic surgery. This single-centre, non-randomised, prospective study demonstrates the potential for PNI to exist exclusively within the central tissue blocks of Mohs specimens.

Understanding overpressure in the FAA aerosol can test by C3H2F3Br (2-BTP).

Thermodynamic equilibrium calculations, as well as perfectly-stirred reactor (PSR) simulations with detailed reaction kinetics, are performed for a potential halon replacement, C3H2F3Br (2-BTP, C3H2F3Br, 2-Bromo-3,3,3-trifluoropropene), to understand the reasons for the unexpected enhanced combustion rather than suppression in a mandated FAA test. The high pressure rise with added agent is shown to depend on the amount of agent, and is well-predicted by an equilibrium model corresponding to stoichiometric reaction of fuel, oxygen, and agent. A kinetic model for the reaction of C3H2F3Br in hydrocarbon-air flames has been applied to understand differences in the chemical suppression behavior of C3H2F3Br vs. CF3Br in the FAA test. Stirred-reactor simulations predict that in the conditions of the FAA test, the inhibition effectiveness of C3H2F3Br at high agent loadings is relatively insensitive to the overall stoichiometry (for fuel-lean conditions), and the marginal inhibitory effect of the agent is greatly reduced, so that the mixture remains flammable over a wide range of conditions. Most important, the flammability of the agent-air mixtures themselves (when compressively preheated), can support low-strain flames which are much more difficult to extinguish than the easy-to extinguish, high-strain primary fireball from the impulsively released fuel mixture. Hence, the exothermic reaction of halogenated hydrocarbons in air should be considered in other situations with strong ignition sources and low strain flows, especially at preheated conditions.

Cold air analgesia in photodynamic therapy of basal cell carcinomas and Bowen's disease: an effective addition to treatment: a pilot study.

BACKGROUND: There is considerable interpatient variability in pain tolerance during and after treatment of skin cancer with photodynamic therapy (PDT). Additionally, erythema and edema are common, with mild crusting and healing over 1 to 2 weeks. OBJECTIVE: To determine whether concurrent cold air analgesia improves the tolerability of PDT. METHOD: Twenty-six patients with two similar superficial skin cancers were treated with PDT. One lesion was treated with cold air analgesia and the other without. Patients rated their pain during treatment using the Wong Baker Faces Pain Scale and detailed duration of posttreatment pain. At week 2, the inflammatory response was assessed. RESULT: A statistically significant difference in the analgesia group was shown with respect to the mean duration of pain and the level of erythema after the first treatment as well as pain scores during the second treatment. CONCLUSION: Patient acceptance of PDT for treatment of nonmelanoma skin cancer is improved with lessened morbidity assessed with concurrent use of cold air analgesia to the treatment field.