Monocytes and macrophages are critical effectors and regulators of inflammation and the innate immune response, the immediate arm of the immune system. Dendritic cells initiate and regulate the highly pathogen-specific adaptive immune responses and are central to the development of immunologic memory and tolerance. Recent in vivo experimental approaches in the mouse have unveiled new aspects of the developmental and lineage relationships among these cell populations. Despite this, the origin and differentiation cues for many tissue macrophages, monocytes, and dendritic cell subsets in mice, and the corresponding cell populations in humans, remain to be elucidated.

/pdf/development-of-monocytes-macrophages-and-dendritic-cells-5fkinpnur8.pdf

Development of Monocytes, Macrophages, and Dendritic Cells

Analysis of Development Edited by Prof Benjamin H Willier, Prof Paul A Weiss and Prof Viktor Hamburger Pp xii + 735 (Philadelphia and London: W B Saunders Company, 1955) 105s

Mechanisms of Development

Influx of macrophages plays a crucial role in tissue repair. However, the precise function of macrophages during the healing response has remained a subject of debate due to their functional dichotomy as effectors of both tissue injury and repair. We tested the hypothesis that macrophages recruited during the diverse phases of skin repair after mechanical injury exert specific functions to restore tissue integrity. For this purpose, we developed a mouse model that allows conditional depletion of macrophages during the sequential stages of the repair response. Depletion of macrophages restricted to the early stage of the repair response (inflammatory phase) significantly reduced the formation of vascularized granulation tissue, impaired epithelialization, and resulted in minimized scar formation. In contrast, depletion of macrophages restricted to the consecutive mid-stage of the repair response (phase of tissue formation) resulted in severe hemorrhage in the wound tissue. Under these conditions, transition into the subsequent phase of tissue maturation and wound closure did not occur. Finally, macrophage depletion restricted to the late stage of repair (phase of tissue maturation) did not significantly impact the outcome of the repair response. These results demonstrate that macrophages exert distinct functions during the diverse phases of skin repair, which are crucial to control the natural sequence of repair events.

https://www.researchgate.net/profile/Rajeev_Ranjan44/publication/41532153_Differential_roles_of_macrophages_in_diverse_phases_of_skin_repair/links/545badb10cf2f1dbcbcaff64.pdf

Differential Roles of Macrophages in Diverse Phases of Skin Repair

Behaviour of activated carbons with different pore size distributions and surface oxygen groups for benzene and toluene adsorption at low concentrations

In recent years, significant advances have been made in the definition of regulatory pathways that control normal and abnormal cardiac valve development. Here, we review the cellular and molecular mechanisms underlying the early development of valve progenitors and establishment of normal valve structure and function. Regulatory hierarchies consisting of a variety of signaling pathways, transcription factors, and downstream structural genes are conserved during vertebrate valvulogenesis. Complex intersecting regulatory pathways are required for endocardial cushion formation, valve progenitor cell proliferation, valve cell lineage development, and establishment of extracellular matrix compartments in the stratified valve leaflets. There is increasing evidence that the regulatory mechanisms governing normal valve development also contribute to human valve pathology. In addition, congenital valve malformations are predominant among diseased valves replaced late in life. The understanding of valve developmental mechanisms has important implications in the diagnosis and management of congenital and adult valve disease.

Heart Valve Development: Regulatory networks in development and disease

Assessing explosion severity of nanopowders with the 20 L sphere

Inherent safety is an alternative way to eliminate or reduce the dust explosion hazard. Inherent safety aims at removing the hazard at the first instance in contrast to hazard acceptation, prevention and mitigation. The key principles to attain an inherently safer design are respectively minimization, substitution, moderation and simplification. These inherent safety principles are reviewed from the dust explosion risk point of view. Some examples are given to illustrate the potential impact of the inherent safer design when applied at the source step of the processes containing combustible dusts or hybrid gassolid mixtures.

/pdf/state-of-the-art-promotion-of-early-inherently-safer-design-5bjaq2s31r.pdf

State of the Art: Promotion of Early Inherently Safer Design Against Dust Explosions

Exploring a new method to study the agglomeration of powders: Application to nanopowders

https://hal.archives-ouvertes.fr/hal-03060213/document

Evaluating the explosion severity of nanopowders: International standards versus reality

Among the factors influencing dust explosion, the particle size distribution (PSD) is both one of the most important and complex to consider. For instance, it is commonly accepted that the explosion sensitivity increases when the particle size decreases. Such an assertion may be questionable for nano-objects which easily agglomerate. However, agglomerates can be broken during the dispersion process. Correlating the explosion parameters to the actual PSD of a dust cloud at the moment of the ignition becomes then essential. The effects of the moisture content and sieving were investigated on a nanocellulose powder and the impact of a mechanical agglomeration was evaluated using a silicon coated by carbon powder. Each sample was characterized before and after dispersion using in situ laser particle size measurement and a fast mobility particle sizer, and explosion and minimum ignition energy tests were conducted respectively in a 20 L sphere and in a modified Hartmann tube. It was observed that drying and/or sieving the nanocellulose mainly led to variations in terms of ignition sensitivity but only slightly modified the explosion severity. In contrast, the mechanical agglomeration of the silicon coated by carbon led to a great decrease in terms of ignition sensitivity, with a minimum ignition energy varying from 5 mJ for the raw powder to more than 1J for the agglomerated samples. The maximum rate of pressure rise also decreased due to modifications in the reaction kinetics, inducing a transition from St2 class to St1 class when agglomerating the dust.

Laurent Perrin

Papers

Assessing explosion severity of nanopowders with the 20 L sphere

State of the Art: Promotion of Early Inherently Safer Design Against Dust Explosions

Exploring a new method to study the agglomeration of powders: Application to nanopowders

Evaluating the explosion severity of nanopowders: International standards versus reality

Safer and stronger together? Effects of the agglomeration on nanopowders explosion