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It has been well established that photonic crystal nanocavities with wavelength sized mode volume enable various integrable photonic devices with extremely small consumption energy and small footprint. In this study, we explore the possibility of non-volatile functionalities employing photonic crystal nanocavities and phase change material, Ge2Sb2Te5 (GST). Recently, non-volatile photonic devices based on GST have attracted significant interest and are expected to enable energy-efficient photonic processing, especially for optical computing. However, the device size and the area of GST in previous studies have been rather large. Here, we propose and fabricate Si photonic crystal nanocavities on which submicron-square GST patterns are selectively loaded. Because of the strong light confinement, extremely small area of GST is sufficient to manipulate the cavity mode. We have succeeded to fabricate 30-nm-thick and several-100nm-square GST blocks patterned at the center of photonic crystal cavity with a high alignment accuracy. We confirmed that the resonant wavelength and Q-factor of cavity modes are controlled by the phase change of GST. Moreover, cavity formation controlled by submicron-sized GST is also demonstrated by GST-loaded photonic-crystal line-defect waveguides. Our approach in which we place sub-micron-sized GST inside a photonic crystal nanocavity is promising for realizing extremely energy-efficient non-volatile integrable photonic devices, such as switches, modulators, memories, and reconfigurable novel devices.
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Photonic topological insulators (PTIs) have been proposed as an analogy to topological insulators in electronic systems. In particular, two-dimensional PTIs have gained attention for the integrated circuit applications. However, controlling the topological phase after fabrication is difficult because the photonic topology requires the built-in specific structures. This study experimentally demonstrates the band inversion in two-dimensional PTI induced by the phase transition of deliberately designed nanopatterns of a phase change material, Ge2Sb2Te5 (GST), which indicates the first observation of the photonic topological phase transition in two-dimensional PTI with changes in the Chern number. This approach allows us to directly alter the topological invariants, which is achieved by symmetry-breaking perturbation through GST nanopatterns with different symmetry from original PTI. The success of our scheme is attributed to the ultrafine lithographic alignment technologies of GST nanopatterns. These results demonstrate how to control photonic topological properties in a reconfigurable manner, providing insight into the possibilities for reconfigurable photonic processing circuits.
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Background In neurosurgical procedures where the park bench position is employed, the risk of perioperative pressure injuries is elevated due to the limited contact surface area, with the head and part of the upper torso extending beyond the surgical table. This study aimed to examine the effects of preventative measures against such injuries, proposing a potential standard for postural fixation in these surgeries. Methods Conducted at a medical center, from January 2017 to March 2023, this prospective cohort study involved participants aged 20 and above who underwent neurosurgical procedures in the park bench position under general anesthesia. The focus was on comparing the incidence of pressure injuries between intervention and control groups. The study adhered to the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) guidelines. Results Out of 65 patients enrolled, 28 were assigned to each of the intervention and control groups. The control group experienced 17 instances of postoperative pressure injuries and skin disorders in areas prone to pressure, such as the axillary and greater trochanter regions. Conversely, the intervention group reported no such incidents, underscoring the efficacy of meticulous surgical positioning and management of bodily pressure, temperature, humidity, and microclimate. Conclusion Implementing preventive measures in neurosurgical park bench procedures significantly reduces the incidence of postoperative pressure injuries and skin disorders. These findings advocate for the adoption of standardized postural fixation protocols in such surgeries, potentially influencing global clinical practices in neurosurgery.
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Nose reconstruction is challenging given the three-dimensional structure and free edge, and various methods have been reported. In general, local flaps provide cosmetic outcomes that are better than those following skin grafts, but there are no published comparative studies on Asians. To determine whether local flaps or skin grafts may optimally be used to reconstruct external nasal defects among Asians. We retrospectively collected data on patients who underwent external nasal tumour resection and reconstruction by 14 plastic surgeons in eight Japanese institutes from 2009 to 2021. The cosmetic results were scored by 14 surgeons using anonymized preoperative and six-month postoperative photographs. Scores for each reconstruction method were statistically evaluated. In total, 86 cases were enrolled; 57 received local flaps and 29 received skin grafts. Most local flaps showed better outcomes compared to skin grafts, but this was not the case for nasolabial and forehead flaps. Notably, local flaps placed in the nasal ala tended to be less successful than flaps placed elsewhere; only the bilobed flap scored better than skin grafts. The defect site did not affect the results of skin grafts. For Asians requiring nasal reconstruction, local flaps provide better cosmetic outcomes than skin grafts, except for those in the nasal ala. Skin grafts may be a good alternative when the bilobed flap is unavailable for the nasal ala.
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Neoplasias Nasais , Rinoplastia , Humanos , Neoplasias Nasais/cirurgia , Neoplasias Nasais/patologia , Estudos Retrospectivos , Nariz/cirurgia , Retalhos Cirúrgicos , Rinoplastia/métodosRESUMO
We present a case of the broncho-pleural fistula with a collapsed lung that was developed 2 weeks after right lower lobectomy. The patient urgently underwent open-window thoracostomy. However, the residual lung remained collapsed. To expand the lung and close the broncho-pleural fistula, negative pressure wound therapy was initiated 20 days after the procedure. The lung expanded within a few days, and the residual thoracic cavity gradually contracted. Subsequently, 2.5 months later, the remaining thoracic cavity was successfully closed using omentoplasty. No recurrence of the broncho-pleural fistula was observed for 1 year. If the lung could be inflated to reduce dead space in the thoracic cavity, broncho-pleural fistula with collapsed lung may be treated with bronchial stump coverage and negative pressure wound therapy.
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Fístula Brônquica , Empiema Pleural , Tratamento de Ferimentos com Pressão Negativa , Doenças Pleurais , Fístula Brônquica/diagnóstico por imagem , Fístula Brônquica/etiologia , Fístula Brônquica/cirurgia , Empiema Pleural/cirurgia , Humanos , Pulmão , Doenças Pleurais/diagnóstico , Doenças Pleurais/etiologia , Doenças Pleurais/cirurgia , PneumonectomiaRESUMO
Epithelioid sarcoma-like hemangioendothelioma is a rare vascular neoplasm that usually occurs in the distal extremities of young adults. Although the overall behavior of this neoplasm is usually indolent with a low risk of distant metastasis, the risk of local recurrence is significant. Therefore, initial surgical treatment with an adequate margin is important to improve the prognosis. However, epithelioid sarcoma-like hemangioendothelioma is frequently misdiagnosed. A preoperative misdiagnosis could result in resection without a sufficient margin. Herein, we describe a 68-year-old man with epithelioid sarcoma-like hemangioendothelioma on the chest wall, which was treated by wide resection despite difficulties with the preoperative diagnosis.