ABSTRACT
Accurate measurements are critical for timely early warning and effective prevention of epidemics due to the continuing impact of bioaerosols on human health. In recent years, researchers have been focused on developing and calibrating online monitoring instruments. However, there is still a lack of laboratory-generated standard aerosol samples suitable for calibration. Therefore, in this study, we utilized a self-developed Ink Jet Aerosol Generator (H-IJAG) to achieve controllable generation of monodisperse aerosol standard particles. The Aerosol Particle Size Spectrometer (APSS, TOPAS 323) was employed as the particle detector. The diameter of the droplet was calculated by measuring the projected area of the droplet in the same image using Image-J software. Experimental results demonstrated that under standardized inkjet parameters, H-IJAG exhibited good reliability and reproducibility, and generated solid particles within (0.4-15) µm. To better simulate the laser-induced fluorescence emission properties of ambient bioaerosol, tryptophan (Trp) and 7-hydroxycoumarin-4-acetic acid (7-HCA) were selected as solutes of the laboratory-generated aerosol samples, which are known bio-fluorescent materials. According to the law of propagation of uncertainty, the relative uncertainty of the volume equivalent diameter of Trp and 7-HCA solid particles by H-IJAG were 0.42 %, while the relative uncertainty of the particle number concentrations of Trp and 7-HCA solid particles generated by H-IJAG were 1.4 %. This optimized IJAG technique provides a promising solution for the accurate calibration of bioaerosol monitors.
ABSTRACT
Purpose: To evaluate the clinical usefulness of digital radiography dacryocystography in patients with primary acquired nasolacrimal duct obstruction prior to endoscopic dacryocystorhinostomy. Methods: All dacryocystography images from 129 patients with primary acquired nasolacrimal duct obstruction were analyzed. Each group was assessed for postoperative epiphora severity using Munk's score via telephone follow-up three years post-surgery. Receiver operating characteristic (ROC) curve was plotted to obtain a suitable cutoff value of the transverse diameter of the lacrimal sac (LS), used to categorize LS size into small (≤4.350 mm) and large (>4.350 mm). Results: Analysis of the transverse diameter of the LS among 129 patients showed a negative correlation between it and Munk's score (r = -0.282, p = 0.001). There was a statistical difference between the surgical outcomes and the sizes of the LS (p = 0.041). The ROC curve analysis showed that the transverse diameter of the LS at 4.350 mm was the ideal cutoff value for the outcome of endoscopic dacryocystorhinostomy, with a sensitivity of 42.2 %, and specificity of 92.3 %. After adjusting for the age and sex, the small LS was associated with an increased risk of postoperative failed outcome (adjusted odds ratio [95 % CI]: 8.628 [1.074, 69.335]). Conclusion: The small LS was independently associated with the failed surgical outcome. Furthermore, the preoperative measurement of the LS transverse diameter serves as one of the reliable predictors for postoperative epiphora severity.
