Convective diffusion from a non-uniformly distributed source in non-Newtonian fluids: a theoretical investigation and experimental confirmation

This work presents a complete theoretical study of the process of convective diffusion from a non-uniformly distributed source in a non-Newtonian fluid flowing through a straight tube. The influence of the governing parameters on the dispersion process is studied and the results are examined in terms of the interaction of rheology, fluid mechanics and diffusion. Experimental studies have been conducted to obtain the diffusivity values of NaOH in aqueous polymer solutions and provide the first test of the potential of this technique for diffusivity measurement in difficult systems

Using In Vitro Granulomas to Identify the Type 1 And Type 3 Interferons In Granuloma Formation and Antimicrobial Activity

The interferons (IFNs) include three major categories of cytokine including type 1 (α, β, ε, κ, and ω), type 2 (γ), and type 3 (λ). Type 3 (IFNs) are further classified into IFNλ1, IFNλ2, IFNλ3, and IFNλ4 in humans and non-human primates (NHPs). These cytokines play important roles in immunity against pathogenic microorganisms where in some cases, they confer protection, and in other cases, they promote pathology. In Mycobacterium tuberculosis (Mtb) infection, type 1 IFNs are known well for their pathogenic roles, whereas the role that type 3 IFNs play in TB is less known and has received little attention. To address this knowledge gap, we made granulomas under in vitro conditions by infecting PBMCs isolated from macaques with Mtb. We pre-treated the PBMCs with IFNs and IFN inhibitors to identify their role in early immune responses in TB. We understood that type I IFNs play a crucial role in promoting granuloma formation and maintenance, while IFN λ signaling shows promise to be a regulator. Interestingly, supplementation with exogenous type I IFN led to a modest reduction in granuloma size, while the addition of IFNλ1 or IFNλ4 resulted in a slight increase in granuloma dimensions. This led to our understanding of the contrasting effects of type I IFN supplementation and IFNλ supplementation on granuloma dimensions, suggesting opposing roles in modulating granuloma formation. A lactose dehydrogenase (LDH) assay was performed to determine if IFN inhibition or supplementation had cytopathic effects in each treatment condition and IFN-supplemented conditions were found to be modestly cytoprotective. To determine how cytokine inhibition or supplementation affected immune responses, we measured cytokine and IDO1 expression. A cytokine bead array performed on the supernatants of the samples led to the identification of IL-1β, TNF-α, and IL-6 exhibiting the highest expression after type I IFN neutralization and a downward trend upon IFN supplementation of both type 1 IFN and IFN λ. The data obtained from flow cytometry suggests that myeloid cells didn’t get influenced by type 3 IFNs to exhibit any change in IDO1 expression

Convective diffusion with reaction in developing flow of a non-Newtonian fluid

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Convective diffusion from a non-uniformly distributed source in flowing blood

The experimental evaluation of solute diffusivity in blood in or near a zero shear rate region poses difficulties, particularly at low hematocrits. This work studies the pertinent theoretical aspects of a possible flow technique which may circumvent these difficulties. The dispersion in a Casson fluid flowing laminarly in a circular tube is studied under the conditions when a solute is injected continuously but non-uniformly from a centrally placed source. The plots of centreline concentration decay as a function of the axial distance as well as the radial concentration profiles are made and their significance for evaluating the diffusivity is critically discussed