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This work is devoted to the emergence of a connected network of slots (cracks) on a square grid. Accordingly, extensive Monte Carlo simulations and finite-size scaling analysis have been conducted to study the site percolation of straight slots with length l measured in the number of elementary cells of the grid with the edge size L. A special focus was made on the dependence of the percolation threshold p_{C}(l,L) on the slot length l varying in the range 1≤l≤L-2 for the square grids with edge size in the range 50≤L≤1000. In this way, we found that p_{C}(l,L) strongly decreases with increase of l, whereas the variations of p_{C}(l=const,L) with the variation of ratio l/L are very small. Consequently, we acquire the functional dependencies of the critical filling factor and percolation strength on the slot length. Furthermore, we established that the slot percolation model interpolates between the site percolation on square lattice (l=1) and the continuous percolation of widthless sticks (l→∞) aligned in two orthogonal directions. In this regard, we note that the critical number of widthless sticks per unit area is larger than in the case of randomly oriented sticks. Our estimates for the critical exponents indicate that the slot percolation belongs to the same universality class as standard Bernoulli percolation.

Objective: The aim of this study was to determine the prevalence of depression among rheumatoid arthritis (RA) Argentinean patients and its association with sociodemographic and clinical factors., Methods: We performed a cross-sectional study of consecutive adults with RA. Sociodemographic data, comorbidities, RA disease activity, and current treatment were assessed. The following instruments were used to evaluate quality of life (EQ-5D-3 L [EURO Quality 5-dimension 3 lines], QOL-RA [Quality of Life-Rheumatoid Arthritis]), functional capacity (HAQ-A [Health Assessment Questionnaire-Argentinean version]), and depression (PHQ-9 [Patient Health Questionnaire 9]; scores 5-9: mild, 10-14: moderate, 15-19: moderate-severe, and ≥20: severe depression, a cutoff value ≥10 is diagnostic of major depression)., Results: Two hundred fifty-eight patients were included, with a median disease duration of 9 years (interquartile range, 3.6-16.7 years). The m PHQ-9 score was 6 (interquartile range, 2-12.3 years). The prevalence of major depression was 33.8%. The frequency of mild, moderate, moderate/severe, and severe depression was 66 (25.6%), 42 (16.3%), 27 (10.5%), and 18 (7%), respectively. Patients with major depression had worse functional capacity (HAQ-A: mean ± SD, 1.6 ± 0.8 vs. 0.7 ± 0.7; p < 0.0001), poorer quality of life (QOL-RA: mean ± SD, 5.4 ± 1.8 vs. 7.3 ± 1.6; p < 0.0001), greater pain (visual analog scale: mean ± SD, 56.2 ± 27.5 mm vs. 33.4 ± 25.7 mm; p < 0.0001), higher disease activity (Disease Activity Score in 28 joints: mean ± SD, 4.3 ± 1.4 vs. 3.3 ± 1.3; p < 0.0001), higher frequency of comorbidities (67% vs. 33%; p = 0.017), and lower frequency of physical activity (22% vs. 35%; p = 0.032). In the multivariate analysis, patients with moderate and severe depression had worse functional capacity (odds ratio, 2.1; 95% confidence interval, 1.6-4.3; p < 0.0001) and quality of life (odds ratio, 0.7; 95% confidence interval, 0.5-0.8; p < 0.0001), independently of disease activity., Conclusions: A third of RA patients in this Argentinean cohort had major depression. In those patients, depression was associated with worst functional capacity and quality of life., Competing Interests: The authors declare no conflict of interest., (Copyright © 2020 Wolters Kluwer Health, Inc. All rights reserved.)

Background: Clinically evident interstitial lung disease (ILD) affects between 10 and 42% of the patients with rheumatoid arthritis (RA). Airway involvement seems to be even more common. Most of the available evidence comes from studies performed in established RA patients. The aim of our study was to know the prevalence of non-diagnosed lung disease (airway and interstitial involvement) in patients with early RA and look for associated factors., Methods: We designed an observational, multicenter, cross-sectional study, and included patients with RA of less than two years since diagnosis. We performed a structured questionnaire, HRCT and lung functional tests looking for lung disease, together with joint disease evaluation. We analyzed which variables were associated with the presence of lung disease on HRCT., Results: We included 83 patients, 83% females. The median (IQR) of time since RA diagnosis was 3 (1-6) months. In the HRCT, 57 patients had airway compromisea (72%), and 6 had interstitial abnormalities (7.5%). The most common altertion found in lung functional tests was a reduced DLCO (14%). The presence of at least one abnormality in the physical exam was associated with lung involvement on HRCT [13 (21.6%) vs 0 (0%); p = 0.026]. Also, patients with lung involvement presented significantly lower values of FVC% and DLCO%, and higher values of RV/TLC. No variable related to joint involvement was found associated with alterations in HRCT., Conclusion: Our study shows that a large proportion of early RA patients has abnormal findings in HRCT. Further studies are required to confirm these findings., (© 2021. The Author(s).)