Mast Cells Initiate Type 2 Inflammation through Tryptase Released by MRGPRX2/MRGPRB2 Activation in Atopic Dermatitis.

Atopic dermatitis (AD) is a common chronic inflammatory skin disease characterized by T helper 2 inflammation as the core pathogenic mechanism. MRGPRX2 plays a key role in nonhistamine allergies and neuroimmune mechanisms in chronic inflammatory dermatitis. However, the role of MRGPRX2 in AD and the development of type 2 inflammation is not yet clear. This study aimed to define the role of MRGPRX2 in type 2 inflammation development and cytokine release in AD by determining its levels in patients with AD and healthy controls. Furthermore, MrgprB2-conditional knockout (MrgprB2-/-) and wild-type mice were used to construct an MC903-induced AD mouse model to observe skin inflammation and cytokine release. Tryptase and its antagonist were applied separately to MrgprB2-/- mice with AD and wild-type mice with AD to confirm the role of the MRGPRB2-tryptase axis in the development of type 2 inflammation in AD. We found that AD severity and type 2 cytokine levels were not associated with IgE levels but were associated with MRGPRX2/MRGPRB2 expression. MrgprB2-/- mice with AD showed milder phenotypes and inflammatory infiltration in the skin than wild-type mice with AD. Tryptase released by MRGPRX2/MRGPRB2 activation is involved in the release of type 2 cytokines, which contributes to inflammatory development in AD.

Experimental study on fluidization behaviors of walnut shell in a fluidized bed assisted by sand particles.

The fluidization behaviors and their differences for walnut shell (WS) assisted by different-sized sands at various blending proportions were investigated experimentally in a cold visual fluidized bed at ambient temperature and pressure. Through analyzing the fluidization characteristic curves, it was found that the WS/sand mixtures were clearly characterized by stratified fluidization during the fluidization process, presenting a velocity interval rather than a threshold for transition from fixed to fluidized bed. Sand-3, as the fluidizing medium, showed better performance for WS fluidization in terms of the relative difference between initial (U mf,i) and final fluidization velocity (U mf,f) as well as the average fluidization rate (R f). Furthermore, the regularity and mechanism of mixing and segregation of WS/sand mixtures in two fluidized regions (semi and completed) are discussed in detail based on the flow pattern diagram, the axial and radial distribution of the components, as well as the mixing index.