Currently, researchers are paying much attention to the development of effective 3D graphene for applications in energy storage and environmental purification. Before commercialization, however, it is necessary to develop a method that allows for the large-scale production of such materials and enables good control over their structural and chemical properties. With this objective, we herein developed a simple method for the formation of large-scale (4 in. wafer) 3D graphene networks via the self-assembly of graphene sheets at a superheated liquid−vapor interface. The structural morphology of this porous network could be modified by controlling the vaporization rate, surface temperature of the target substrate, and amount of discharged colloids. The key mechanism behind this intriguing result was investigated by high-speed visualization of microdroplet behavior and extensive thermal analysis. This self-assembled 3D graphene had excellent electrical and mechanical properties. Our approach can be directly used for the mass production of graphene-based materials.
ImportanceFungal endophthalmitis caused by contaminated medical products is extremely rare; it follows an intractable clinical course with a poor visual prognosis.ObjectiveTo report the epidemiologic and clinical features and treatment outcomes of a nationwide fungal endophthalmitis outbreak after cataract surgery as a result of contaminated viscoelastic agents in South Korea.Design, Setting, and ParticipantsThis was a retrospective case series analysis of clinical data from multiple institutions in South Korea conducted from September 1, 2020, to October 31, 2021. Data were collected through nationwide surveys in May and October 2021 from the 100 members of the Korean Retinal Society. Patients were diagnosed with fungal endophthalmitis resulting from the use of the viscoelastic material sodium hyaluronate (Unial [Unimed Pharmaceutical Inc]). Data were analyzed from November 1, 2021, to May 30, 2022.Main Outcomes and MeasuresThe clinical features and causative species were identified, and treatment outcomes were analyzed for patients who underwent 6 months of follow-up.ResultsThe fungal endophthalmitis outbreak developed between September 1, 2020, and June 30, 2021, and peaked in November 2020. An official investigation by the Korea Disease Control and Prevention Agency confirmed contamination of viscoelastic material. All 281 eyes of 265 patients (mean [SD] age, 65.4 [10.8] years; 153 female individuals [57.7%]) were diagnosed with fungal endophthalmitis, based on clinical examinations and supportive culture results. The mean (SD) time period between cataract surgery and diagnosis was 24.7 (17.3) days. Patients exhibited characteristic clinical features of fungal endophthalmitis, including vitreous opacity (212 of 281 [75.4%]), infiltration into the intraocular lens (143 of 281 [50.9%]), and ciliary infiltration (55 of 281 [19.6%]). Cultures were performed in 260 eyes, and fungal presence was confirmed in 103 eyes (39.6%). Among them, Fusarium species were identified in 89 eyes (86.4%). Among the 228 eyes included in the treatment outcome analysis, the mean (SD) best-corrected visual acuity improved from 0.78 (0.74) logMAR (Snellen equivalent, 20/120 [7.3 lines]) to 0.36 (0.49) logMAR (Snellen equivalent, 20/45 [4.9 lines]) at 6 months. Furthermore, disease remission with no signs of fungal endophthalmitis (or cells in the anterior chamber milder than grade 1) was noted in 214 eyes (93.9%).Conclusions and RelevanceThis was a retrospectively reviewed case series of a fungal endophthalmitis outbreak resulting from contaminated viscoelastic material. Findings of this case series study support the potential benefit of prompt, aggressive surgical intervention that may reduce treatment burden and improve prognosis of fungal endophthalmitis caused by contaminated medical products.
As novel technologies have been developed, emissions of gases of volatile organic compounds (VOCs) have increased. These affect human health and are destructive to the environment, contributing to global warming. Hence, regulations on the use of volatile organic compounds have been strengthened. Therefore, powerful adsorbents are required for volatile organic compounds gases. In this study, we used graphene powder with a mesoporous structure to adsorb aromatic compounds such as toluene and xylene at various concentrations (30, 50, 100 ppm). The configuration and chemical composition of the adsorbents were characterized using scanning electron microscopy (SEM), N 2 adsorption-desorption isotherm measurements, and X-ray photoelectron spectroscopy (XPS). The adsorption test was carried out using a polypropylene filter, which contained the adsorbents (0.25 g), with analysis performed using a gas detector. Compared to graphite oxide (GO) powder, the specific surface area of thermally expanded graphene powder (TEGP800) increased significantly, to 542 m 2 g −1 , and its chemical properties transformed from polar to non-polar. Thermally expanded graphene powder exhibits high adsorption efficiency for toluene (92.7–98.3%) and xylene (96.7–98%) and its reusability is remarkable, being at least 91%.
Closed-box loudspeaker systems (CBLSSs) are compact and simple air-suspension loudspeaker systems, and their low-frequency responses are determined by two fundamental parameters: resonance frequency and total damping. Recently, electronic devices have come to require more compact designs, so the volumes of loudspeaker should be reduced. However, a small loudspeaker cannot retain sufficient acoustic space, resulting in poor low-frequency acoustic performance. Herein, we investigated acoustic characterization of the CBLSS with different filling materials such as thermally expanded graphene oxide (TEGO), activated carbon, graphene platelets, and melamine foam (MF). Upon the powder-based test, the resonance frequency of the loudspeaker decreased and resulted in a volume increasing effect inside of the loudspeaker. The TEGO shows almost double volume increase rate, compared to other particle-based filling materials. Employing hybrid filling material that consists of TEGO in an MF cage (TEGO@MF), the volume increase rate of the novel loudspeaker was over 24% at 300 cc. Because of the high adsorptive characteristics and thermal properties of TEGO, the acoustic performance in the low-frequency domain was clearly enhanced, despite the reduced mass loading. Furthermore, these properties were observed to be highly effective for enhancing the low-frequency acoustic performance of the larger loudspeaker, achieving a volume increase rate of 49.5% in a 700 cc enclosure.
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