Field localization of hexagonal and short-range ordered plasmonic nanoholes investigated by cathodoluminescence.

Plasmonic nanoholes have attracted significant attention among nanoplasmonic devices, especially as biosensing platforms, where nanohole arrays can efficiently enhance and confine the electromagnetic field through surface plasmon polaritons, providing a sensitive detection. In nanohole arrays, the optical resonances are typically determined by the inter-hole distance or periodicity with respect to the surface plasmon wavelength. However, for short-range ordered (SRO) arrays, the inter-hole distance varies locally, so the plasmon resonance changes. In this study, we investigate the local resonance of SRO nanoholes using a cathodoluminescence technique and compare it with hexagonally ordered nanoholes. The cathodoluminescence photon maps and resonance peak analysis reveal that the electric fields are confined at the edges of holes and that their resonances are determined by inter-hole distances as well as by their distributions. This demonstrates the Anderson localization of the electromagnetic waves showing locally enhanced electromagnetic local density of states in SRO nanoholes.

Highly sensitive pressure and temperature induced SPP resonance shift at gold nanohole arrays.

Short range ordered (SRO) plasmonic nanohole arrays have a distinct surface plasmon polariton resonance in the visible region and exhibit an excellent sensing capability toward changes in the surrounding refractive index. While SRO and perfectly ordered plasmonic hole arrays have similar sensing properties, SRO arrays have clear advantages in fabrication, simplicity, and scalability. In this study, we use SRO gold nanoholes, which are subjected to pressure and temperature cycles, for vacuum and temperature sensing. The response of the transmission spectra to pressure changes in the range 10-3-105 Pa and temperature scans in the range 20-400 °C was recorded. Upon pressure cycling, a reversible response was observed. Upon initial temperature annealing, an irreversible blue shift in the resonance dip position was observed. Upon further temperature cycling, the resonance dip position shifts reversibly, with a notable red shift upon temperature increase. The results are discussed and interpreted based on possible molecular adsorption/desorption upon pressure cycling and in terms of the gold film's recrystallization, thermal expansion, and free electron density variations.

Deep Inferior Epigastric Perforator Flap for Immediate Breast Reconstruction following Mastectomy in Breast Cancer Patients: An Initial Experience in Vietnam.

Background: Breast reconstruction in breast cancer patients is an optional surgery that improves the quality of life while preserving the efficacy of chemotherapy and radiotherapy. Deep inferior epigastric perforator (DIEP) flap is a new but reliable and safe technique for autologous breast reconstruction. After mastectomy, immediate reconstruction is the preferred method because of its aesthetic result and convenience. This study is aimed at summarizing our experience in DIEP flap for immediate breast reconstruction. Methods: A prospective study was performed on 30 breast cancer patients who underwent intermediate breast reconstruction for DIEP flap after mastectomy from June 2019 to June 2021 in Hanoi Medical University Hospital. Clinicopathology characteristics, tumor stage, treatment, and complications were evaluated. Result: The mean age of patients was 44.9 (range: 29-73 years). 86.7% of patients were in stages I and II. Five patients (16.7%) received neoadjuvant chemotherapy. 20 patients (66.7%) underwent nipple-sparing mastectomy (NSM) procedures. The mean operating time was 341 minutes. The mean time to receive chemotherapy was 34.68 days. The mean number of perforators was 1.30. The overall flap success rate was 90%. Twelve patients (40%) experienced complications. Four patients (13.3%) returned to the operating room due to venous congestions. Two patients (6.67%) had complete flap loss. Other complication: fat necrosis (6.7%), seroma (13.3%), partial flap loss (3.3%), abdominal wound dehiscence (6.7%), pneumonia (3.3%), and pulmonary embolism (6.7%). After one-month postoperation, 88.9% of patients were satisfied with their breasts, and 74.07% were satisfied with the operation. Conclusion: DIEP flap is a new but reliable and safe technique for autologous breast reconstruction. Though patients opting for breast reconstruction still have a low risk of complication and reconstruction failure, this procedure should be used more frequently in appropriate patients to improve their quality of life.