Raman Spectroscopy Investigation of Graphene Oxide Reduction by Laser Scribing

Laser scribing has been proposed as a fast and easy tool to reduce graphene oxide (GO) for a wide range of applications. Here, we investigate laser reduction of GO under a range of processing and material parameters, such as laser scan speed, number of laser passes, and material coverage. We use Raman spectroscopy for the characterization of the obtained materials. We demonstrate that laser scan speed is the most influential parameter, as a slower scan speed yields poor GO reduction. The number of laser passes is influential where the material coverage is higher, producing a significant improvement of GO reduction on a second pass. Material coverage is the least influential parameter, as it affects GO reduction only under restricted conditions.

Synthesis of Air-Stable Cu Nanoparticles Using Laser Reduction in Liquid

We report the synthesis of air-stable Cu nanoparticles (NPs) using the bottom-up laser reduction in liquid method. Precursor solutions of copper acetlyacetonate in a mixture of methanol and isopropyl alcohol were irradiated with femtosecond laser pulses to produce Cu NPs. The Cu NPs were left at ambient conditions and analyzed at different ages up to seven days. TEM analysis indicates a broad size distribution of spherical NPs surrounded by a carbon matrix, with the majority of the NPs less than 10 nm and small numbers of large particles up to ∼100 nm in diameter. XRD collected over seven days confirmed the presence of fcc-Cu NPs, with some amorphous Cu2O, indicating the stability of the zero-valent Cu phase. Raman, FTIR, and XPS data for oxygen and carbon regions put together indicated the presence of a graphite oxide-like carbon matrix with oxygen functional groups that developed within the first 24 h after synthesis. The Cu NPs were highly active towards the model catalytic reaction of para-nitrophenol reduction in the presence of NaBH4.

Laser Reduction Glottoplasty for Voice Feminization: Experience on 28 Patients

Objectives: Laser reduction glottoplasty is a relatively new surgical procedure for voice feminization on transgender women. This study aims to determine long-term voice results of glottoplasty on transwomen. Methods: Nonrandomized, retrospective, cohort. Tertiary referral center. Endoscopic laser reduction glottoplasty was performed on 28 transwomen. Voice Handicap Index (VHI-30), Transsexual Voice Questionnaire (TVQ), acoustic analysis with /a/ for F0, jitter, shimmer, noise to harmonic ratio and acoustic analysis for speaking F0 were measured before and after surgery. Patients self-evaluated their postoperative voices and medical students and 2 voice experts scored patients’ pre- and postsurgery voice samples as masculine, feminine or neither. Results: Mean total VHI and TVQ scores improved significantly postoperatively ( P < .001). Pre- and postsurgery mean F0 were 132 and 198 Hz and mean speaking F0 were 123 and 194 Hz, respectively; these variations were found statistically significant ( P < .001). Postoperative mean jitter, shimmer and NHR increased significantly compared to preoperative values ( P < .05). Nine patients (32%) were not happy with their postsurgery voice result and were offered anterior glottic web formation as secondary procedure. MFT women’s self-ratings of their postsurgery voices showed 3 masculine, 19 feminine and 6 neither outcomes, leading to patient gratification score of 68%. Medical students evaluated 79% of postsurgery voice specimens as feminine. Voice experts evaluated 75% of postsurgery voice specimens as feminine. Conclusions: Laser reduction glottoplasty is an accomplished and satisfying operation for feminizing voice of transwomen. Its voice outcome appears to be durable for 5 years. However, secondary operation may be needed to further gratify transwomen.