ABSTRACT
Vertically stacking two-dimensional materials into van der Waals (vdW) heterostructures (HS) is deemed to be an effective strategy to tailor their physical properties and enrich their applications in modern nanoelectronics. Here, we study the geometry, electronic, and optical properties of Janus Ga2SeTe/In2SSe heterostructures by using first-principles calculations. We consider four models of Ga2SeTe/In2SSe heterostructures with an alternative chalcogen atom layer sequence and five potential stacking configurations, and find that the most energy favorable stacking pattern is AB stacking for each model. The heterostructures form type II alignment with a direct band gap. Moreover, the band gap values are highly dependent on the magnitude of the electric dipole, which is related to the sublayer intrinsic dipole direction and interface charge transfer. Additionally, the optical absorption of the heterostructures is intensified in the visible and ultraviolet regime. Furthermore, we predict two heterostructures with the band edge straddling the water redox potential level. These findings can help in understanding the tailored properties of the heterostructures based on Janus two-dimensional materials, and guide experiments in designing novel optoelectronic devices.
ABSTRACT
: This study aims to assess the in vitro activity of different samples of cefoperazone/sulbactam (CFP/SUL) against multidrug-resistant organisms (MDROs). Clinical isolates of extended-spectrum ß-lactamase (ESBL)-Escherichia coli, ESBL-Klebsiella pneumoniae, carbapenem-resistant Acinetobacter baumannii (CR-AB), and carbapenem-resistant Pseudomonas aeruginosa (CR-PA) were collected. The minimum inhibitory concentration (MIC) and time-killing methods were used to assess and compare the in vitro activities of different samples of cefoperazone/sulbactam (CFP/SUL) against these MDROs. For ESBL-E. coli, ESBL-K. pneumoniae, and CR-PA, product C had smaller variations than product A and B (p < 0.05). For CR-AB, product B had the largest variation compared to the other two products (p < 0.05). In the time-killing studies, significant differences among the products when used at 16/16 µg/mL were noted for ESBL-E. coli, ESBL-K. pneumoniae, and CR-AB isolates. In conclusion, this study demonstrated the significantly different activity of different products of CFP/SUL against MDROs.
ABSTRACT
Three-dimensional functionalized graphene monoliths (3DFGMs) have attracted intensive attention as energy storage materials due to their unique interconnected porous structure, good electrical conductivity, excellent mechanical strength, and pseudocapacitive characteristic. Herein, we report a facile, green and low-cost strategy through a simple, one-step electrochemical process in a phytic acid solution to fabricate a 3DFGM. The 3D porous structure and functionalization of graphene can be obtained simultaneously. The as-obtained 3DFGM that consists of 3D porous O, P-functionalized few-layer graphene shows high specific surface area and good electrical conductivity. The 3DFGM with these characteristics exhibits excellent electrochemical performance, including an ultrahigh specific areal capacitance of 485 mF cm-2, superior rate performance, and outstanding cycling stability. Most importantly, the assembled 3DFGM//3DFGM symmetric supercapacitor exhibits a high specific areal capacitance of 225 mF cm-2 and delivers a maximum energy density of 1.2 W h L-1 and a power density of 560 W L-1 in aqueous electrolyte. Therefore, this work provides a promising method for the future design and fabrication of high performance 3D functionalized graphene-based electrodes for energy storage devices.
ABSTRACT
BACKGROUND: Clinical information about bacteremia due to extended-spectrum ß-lactamase (ESBL)-producing pathogens in cancer patients was limited. The study was aimed to identify the clinical manifestations and risk factors for mortality in ESBL-producer bacteremia in cancer patients. METHODS: A retrospective study of bacteremia caused by ESBL-producing Escherichia coli or Klebsiella pneumoniae in adults with cancer in National Cheng Kung University Hospital and National Taiwan University Hospital from July 2002 to August 2007 was conducted. Clinical characteristics, initial manifestations, and antimicrobial therapy were analyzed for their association with crude mortality at 14 days after bacteremia onset. RESULTS: A total 113 episodes of bacteremia caused by E coli (59.3%), K pneumoniae (39.8%) or both (0.9%) were included. Patients with hematological malignancy were younger (55 ± 22 vs. 69 ± 14 years, p < 0.003) and had less co-morbidity, but were more likely to have neutropenia (73.1% vs. 4.6%, p < 0.001) than those with solid tumor. By the univariate analysis in 113 episodes of ESBL-producer bacteremia, several risk factors, including pneumonia or soft-tissue infection as the bacteremia source, initial manifestations with high Pitt bacteremia scores, shock, respiratory failure or severe sepsis, and inappropriate definitive therapy were associated with 14-day crude mortality. By multivariate analysis, only pneumonia [adjusted odds ratio (AOR), 5.2; 95% confident interval (CI), 1.3-21.0; p = 0.021], severe sepsis (AOR, 24.3; 95% CI, 5.6-105.0; p < 0.001), and inappropriate definitive therapy (AOR, 11.3; 95% CI, 1.7-72.8; p = 0.011) were independently associated with a fatal outcome. CONCLUSION: The presence of neutropenia or underlying hematological malignancy in cancer patients with ESBL-producer bacteremia was not associated with an increase in the mortality rate. Appropriate definitive antimicrobial therapy will be beneficial in improving clinical outcome.
