Near-infrared radiation induced attenuation in nested anti-resonant nodeless fibers.

This Letter reports the first, to the best of our knowledge, spectral radiation induced attenuation (RIA) measurements of nested anti-resonant nodeless hollow-core fibers (NANFs). A 5-tube NANF, alongside a solid-core single-mode radiation resistant fiber (SM-RRF), was irradiated under γ-ray up to 101 kGy (SiO2) and under x-ray up to 241 kGy (SiO2). No RIA was observed in the NANF in the second half of the O-band, the S-band, the C-band, and the L-band. The NANF showed a reduction of absorption bands associated with water and HCl under irradiation. Three new attenuation peaks were radiolytically induced and are attributed to the creation of HNO3. These peaks are centered respectively at 1441 nm, 1532 nm, and 1628 nm, with a full width at half maximum (FWHM) of, respectively, 10 nm, 12 nm, and 12 nm. These results demonstrate that the wide bandwidth range of NANFs is essentially unaffected by radiation, but the internal gas contents of the NANF must be managed to avoid producing undesirable spectral features through radiolytic reactions. Wide spectral regions almost unaffected by the ionizing radiation could open new possibilities for the use of NANF in harsh radiation environments.

Free flap transfers for head and neck and skull base reconstruction in children and adolescents - Early and late outcomes.

OBJECTIVES: Reconstruction of surgical defects by free tissue transfer following resection of head and neck tumors in children are sparse. This study aims to assess the feasibility and safety of free flap reconstruction following surgical ablation of head and neck and skull base tumors in children based on our experience and the recent literature. METHODS: Data from medical files of all children and adolescents <18 years of age who underwent free flap reconstruction following resection of head and neck and skull base tumors at our tertiary center between 2000 and 2018 were retrospectively reviewed. Data on early and late complications at the primary and donor sites, functional and aesthetic outcome, and tumor control were analyzed. RESULTS: Twenty-four children (mean age 11.3 ± 5.1 years) were enrolled. Early complications occurred in 14 (56%) and late complications occurred in 8 (32%) of the procedures, with surgical intervention required in 4 (16%). Prior chemoradiation, sarcoma, non-reanimation procedures, and the use of rectus abdominis free flaps were associated with higher complication rates. The final functional and cosmetic outcomes, including mastication, deglutition, and speech, were satisfactory in all patients with one exception. CONCLUSIONS: Free flap transfer is a safe and feasible technique for reconstructing head and neck and skull base defects following surgical excision of tumors in children. Early identification and precautionary measures against the effects of potential causes of complications may improve outcome. Larger international cohort studies are warranted.