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In this study, surface dust samples were collected within the second ring road of Shenyang City under different land-use types, and the concentration and chemical speciation of metals in different particle sizes under different land-use types were analyzed. Dust samples were separated into four particle size fractions (＜50, 50–100, 100–500, 500–2000 μm), and particles in the range of 100–500 µm were the highest representing one-third of the dust mass. The results revealed that metals were detected in order Zn > Cr > Pb > Cu > Ni > As > Cd in different particle sizes of dust under different land-use types. The relative contribution of individual particle-size fractions for seven metals was different, but the results showed preferential partitioning to small particle-size fractions. The relative contribution of metals in individual particle-size fractions and chemical speciation were significantly affected by the type of land use. Metals concentrated on the smaller particles in the traffic area, and the particles (<50 µm) contained the highest percentage of metals but Cr. The residual fractions (F5) of Ni, Cr, As and Cu overall represented the predominant portion in different particle size of fractions under different land-use types, Zn and Pb were mostly bound to the Fe–Mn oxides-bound fraction (F3), and the exchangeable fraction (F1) accounted for a relatively large proportion of Cd. The results of the risk assessment code (RAC) of Cd indicated that the risk of Zn was medium, and it was high for Cd in the dust of Shenyang City. [ABSTRACT FROM AUTHOR]

Objectives: Idiopathic inflammatory myopathy (IIM) is a group of systemic autoimmune diseases characterised by muscle involvement. This study aims to reveal the characteristics of IIM subtypes and explore the molecular mechanisms underlying IIM., Methods: The STRING database was utilised to construct a protein-protein interaction network of differentially expressed genes obtained from the GSE128470, GSE3112, and GSE39454 datasets. The immune cell infiltration level was assessed by CIBERSORT in polymyositis (PM). Experimental autoimmune myositis (EAM) model mice were constructed for experimental verification. Serum levels of soluble CD44 (sCD44) were measured using enzyme-linked immunosorbent assay., Results: The upregulated hub gene CD44 was highly expressed in inflammatory cells infiltrating the skeletal muscle of patients with PM and in EAM mice. CD44 was correlated with both M1 macrophages (r=0.57, p<0.0001) and M2 macrophages (r=0.57, p<0.0001) in PM. Additionally, CD44+F4/80+ macrophages in skeletal muscle were increased (p<0.0001) and CD44 showed a stronger association with markers of M1 macrophage in EAM mice. Moreover, serum sCD44 levels were elevated in patients with IIM (p=0.0024), PM (p=0.0332) and dermatomyositis (p=0.0001) notably in the anti-melanoma differentiation-associated gene 5 antibody positive subtype (p=0.0007). sCD44 levels also positively correlated with visual analogue score (r=0.4424, p=0.0013), myositis intention to treat activity index (r=0.3938, p=0.0047), skin damage score (r=0.3796, p=0.0101) and skin activity score (r=0.4625, p=0.0014) in patients with IIM., Conclusions: This study suggests that macrophages expressing CD44 may be involved in the pathogenesis of PM, and sCD44 could serve as a potential marker for skin damage and activity in IIM.