An advantage of the HRMAS technique over solid-state MAS resides in the presence in HRMAS probes of gradients coils (Fig. 1), which may not only further improve spectral resolution, but also select coherence pathways and permit diffusion experiments to differentiate molecular species according to their degree of mobility in hydrated matrices.
The top channel (60 µm height, 800 µm width) contains a confluent monolayer of human dermal microvascular endothelial cells (HDMECs) (Figure 1C) cultured on the polyester membrane with 400 nm pores to permit diffusion of biomolecules between the top and bottom channels (Figure 1B) as used in traditional Transwell inserts for cell culture.
It is chosen so that it permits diffusion in homogenous areas but not between boundaries.
The inserts permitted diffusion of any soluble growth factors produced by the fibroblasts but prevented direct contact between the cells.
Even in exosporium-bearing species, the coat still makes significant (albeit indirect) contact with the environment, since the exosporium permits diffusion of small molecules.
The mesh still permitted diffusion of the pollen odor, meaning both pollen and sucrose-rewarded bees were exposed to pollen odor during training.
The conformational changes during binding occur mainly in TM α-helices 1, 4, 7 and 10 that cause the occlusion by the intracellular α-helices to open, thereby permitting diffusion [ 12].
The natural vitreous body acts as a viscoelastic damper; it is hydrophilic, permits diffusion of oxygen, ions, and small particles, and blocks fluid movement and shear stress over the retina.
Demineralized dentin permeable to dyes, whether formed by acid-base cements before setting or formed by incomplete infiltration of resin [ 22, 23], permits diffusion of acid which subsequently may result in tooth hypersensitivity, short-term detachment of restorations, secondary caries, and pulpal pathology [ 4– 8, 24– 26].
The relative stability and uncharged nature of H2O2 may permit its diffusion through membranes, though this diffusion would be less rapid than that of gases, such as nitric oxide (NO) and hydrogen sulfide (H2S).
Micro-CT analysis confirmed the presence of an extensive system of macropores, sufficiently connected to permit protein diffusion, but an absence of high volume, inter-pore channels.
