RESUMO
Based on density functional theory investigation, we exposed the potential application of hexagonal Sb2C3 nanosheet as highly sensitive material for nitrogen-containing gases (NCGs) NH3, NO2 and NO molecules. Our rigorous simulations show that NH3, NO2 and NO molecules shows physisorption on the Sb2C3 nanosheet via vdW DFT-D3 interactions. The calculations were carried out by considering that the monolayer Sb2C3 as the sensor material modulated with its electrical conductivity when its surface adsorbs the gas molecules for their various orientations and positions. It is also found that the magnetic properties are induced in non-magnetic Sb2C3 nanosheet by adsorption of NO molecule. The interaction of the Sb2C3 nanosheet with the gas molecules is further analysed by the charge density difference (CDD), electrostatic potential (ESP) and Bader charge analysis. Our analysis indicates a strong possibility for the detection of NO2 and NO gas molecules by the Sb2C3 based sensor, due to the associated significant changes in the conductivity and reasonable adsorption energy. Also, in the visible region at T = 300 K, very low recovery times have been found as 431 µs, 785.01 s and 53.8 µs for NH3, NO2 and NO, respectively, which strongly suggest the Sb2C3 nanosheets as a better reversible multi-time gas sensor material towards the NCGs adsorption. We also explored the humidity effect on the NCGs based 2D Sb2C3 sensor material. The current-voltage (I-V) characteristics also confirmed the suitability of 2D Sb2C3 in real-time applications. Overall, present work reveals that the 2D Sb2C3 nanosheets as a promising material for semiconductor-based nano sensors for environmentally hazard pollutants like NCG molecules.
RESUMO
To study correlation of different optical coherence tomography (OCT) patterns of diabetic macular edema (DME) with systemic risk factors. Institutional cross-sectional double-masked non-interventional study with 330 eyes of middle-aged male type 2 diabetes patients with DME. Various systemic parameters were measured. Diffuse retinal thickening (DRT), cystoid and serous patterns of DME were identified on OCT. Comparison between DRT versus non-DRT and serous versus non-serous eyes was done in respect to systemic parameters. Correlation of serous and DRT pattern was tested with systemic parameters above and below specified values. Mean age was 54.4 ± 7.1 years. Mean duration of diabetes was 8.7 ± 4.2 years. Mean serum globulin level was significantly higher (p = 0.018) in serous compared to non-serous group. Prevalence of serous DME was significantly high in those with serum globulin level >3.5 gm/dl (prevalence ratio = 3.01, p = 0.040). Significant correlation of central macular thickness was observed with duration of diabetes (p = 0.002, r = 0.440).Visual acuity (logMAR) was correlated significantly with HbA1C (p = 0.031, r = 0.305). Increased serum globulin, a positive phase reactant of inflammation, was found significant independent risk factor for development of serous DME. This study did not identify any modifiable systemic factor for any of the OCT patterns in DME.