Normative data and correlation parameters for vessel density measured by 6 × 6-mm optical coherence tomography angiography in a large chinese urban healthy elderly population: date from the Beichen eye study.

BACKGROUND: To establish a normative database for macular vessel density (VD) measured by optical coherence tomography angiography (OCTA) and explore the parameters related to the VD. METHODS: An observational study in epidemiology. 5840 healthy elderly participants in Beichen district, Tianjin, China underwent detailed ophthalmic and systemic examinations. OCTA was performed in all subjects using a 6 × 6-mm line scan mode centered on the macula and the built-in software was used to quantify VD and stratify the retina. RESULTS: One thousand four hundred sixty-one healthy elderly citizens (30.4% men) were included, with a median age of 60.0 years (8.0 years) and an age range of 50 to 87 years.VDs in the different plexuses: superficial capillary plexus (SCP) 43.9% (3.2%), deep capillary plexus (DCP) 44.3% (2.8%), outer capillary plexus (OCP) 21.9% (5.9%), choriocapillaris (CC) 52.1% (1.4%). 90% medical reference range of the VDs at different plexuses was reported. Age was correlated with the VDs of each capillary plexus. Sex was correlated with the VDs of DCP and OCP, and the VDs of DCP (p < 0.001) and OCP (p = 0.015) in women were higher than that in men. After age and sex adjustment, choroid average thickness was positively correlated with VDs of SCP (R = 0.067, p = 0.010) and DCP (R = 0.108, p < 0.001), ganglion cell layer (GCL) average thickness (R = 0.072, p = 0.006) was positively correlated with the VD of OCP, best-corrected visual acuity (BCVA) (R = 0.082, p = 0.002) was positively correlated with the VD of CC. CONCLUSIONS: In this study, the normative VD database of the Chinese urban healthy elderly population measured by the OCTA was established, and parameters related to the VD of each capillary plexus were analyzed, providing new ideas for the future study of the relationship between macular VD and disease. TRIAL REGISTRATION: The Beichen Eye Study had been registered on the Chinese Clinical Trial Registry website (registry number: ChiCTR2000032280) on April 25, 2020.

[Analysis of Characteristic Eye Movement Behaviors of Young Adults with Different Degrees of Myopia].

Objective: To measure the parameters of eye movement of young adult patients of myopia, to compare the differences in the parameters of patient groups with varied degrees of myopia, and to analyze the correlation between eye movement parameters and axial length (AL) and spherical equivalent refraction (SER). Methods: A total of 91 young adult patients of myopia were recruited. The subjects were divided into three groups of low, moderate, and high myopia according to their SER. Information on the subjects' age and sex was collected and general clinical examination was completed. The subjects' binocular fixation, reflexive saccade, and antisaccade were measured with eye tracker. One-way ANOVA or Kruskal-wallis test was used to compare the general data and eye movement parameters of the three groups of myopic patients. Pearson or Spearman correlation analysis was used to analyze AL and SER's correlation with 95% bivariate contour ellipse area (BCEA) and saccadic parameters. Results: The 95% BCEA for mild, moderate, and high myopia groups were 2.08 (0.54, 14.69) deg 2, 4.99 (0.94, 49.22) deg 2, and 5.79 (2.18, 64.91) deg 2, respectively. There was significant difference between the 95% BCEA of the three groups ( P=0.029). The 95% BCEA of the mild myopia group was significantly smaller than that of the high myopia group ( P=0.01). There were no significant differences in saccadic parameters among the three groups ( P>0.05). There was a significant positive correlation between 95% BCEA and AL ( r=0.342, P=0.001). There was a significant negative correlation between 95% BCEA and SER ( r=-0.322, P=0.002). There was no significant correlation between the parameters of saccadic movement and the AL or SER ( P>0.05). Conclusion: For young adult myopic patients, the longer the AL is, the higher the degree of the myopia and the worse the fixation stability becomes. The fixation stability of patients with high myopia was significantly worse than that of patients with mild myopia. There was no significant difference in saccadic parameters in patients with different degrees of myopia.

Adaboost Algorithm in Artificial Intelligence for Optimizing the IRI Prediction Accuracy of Asphalt Concrete Pavement.

The international roughness index (IRI) for roads is a crucial pavement design criterion in the Mechanistic-Empirical Pavement Design Guide (MEPDG). However, studies have shown that the IRI transfer function in the MEPDG is simply a linear combination of road parameters, so it cannot provide accurate predictions. To solve this issue, this research developed an AdaBoost regression (ABR) model to improve the prediction ability of IRI and compared it with the linear regression (LR) in MEPDG. The development of the ABR model is based on the Python programming language, using the 4265 records from the Long-Term Pavement Performance (LTPP) that include the pavement thickness, service age, average annual daily truck traffic (AADTT), gator cracks, etc., which are reliable data that are preserved after years of monitoring. The results reveal that the ABR model is significantly better than the LR because the correlation coefficient (R2) between the measured and predicted values in the testing set increased from 0.5118 to 0.9751, and the mean square error (MSE) decreased from 0.0245 to 0.0088. By analyzing the importance of variables, there are many additional crucial factors, such as raveling and bleeding, that affect IRI, which leads to the weak performance of the LR model.

Experimental Study of the Mechanical and Microstructure Characteristics of Coal Gangue Road Stabilization Materials Based on Alkali Slag Cementation.

To accelerate the resource utilization of coal gangue and meet the strategic requirements of carbon neutralization, alkali-activated, slag-cemented coal gangue is applied in the preparation of solid waste-based road stabilization materials. Here, the cementation characteristics and microstructure characteristics of alkali-activated, slag-cemented coal gangue road stabilization materials are studied using the alkali equivalent and coal gangue aggregate ratio as experimental variables. The results show that with the increase in alkali equivalent from 1% to 7%, the unconfined compressive strength of the alkali-activated coal gangue road stabilization material initially increases and then decreases, with 3% being the optimal group in terms of stabilization, the aggregate ratio of coal gangue increases from 70% to 85%, and the 7-day unconfined compressive strength of the stabilized material decreases approximately linearly from 8.16 to 1.68 MPa. At the same time, the porosity gradually increases but still meets the requirements of the specification. With the increase in hydration time, a large number of hydration products are formed in the alkali slag cementation system, and they are closely attached to the surface of and interweave with the coal gangue to fill the pores, resulting in the alkali slag slurry and coal gangue being brought closer together.