Growth limiting conditions and denitrification govern extent and frequency of volume detachment of biofilms

This study aims at evaluating the mechanisms of biofilm detachment with regard of the physical properties of the biofilm. Biofilms were developed in Couette–Taylor reactor under controlled hydrodynamic conditions and under different environmental growth conditions. Five different conditions were tested and lead to the formation of two aerobic heterotrophic biofilms (aeHB1 and aeHB2), a mixed autotrophic and heterotrophic biofilm (MAHB) and two anoxic heterotrophic biofilms (anHB1 and anHB2). Biofilm detachment was evaluated by monitoring the size of the detached particles (using light-scattering) as well as the biofilm physical properties (using CCD camera and image analysis). Results indicate that volume erosion of large biofilm particles with size ranging from 50 to 500 lm dominated the biomass loss for all biofilms. Surface erosion of small particles with size lower than 20 lm dominates biofilm detachment in number. The extent of the volume detachment events was governed by the size of the biofilm surface heterogeneities (i.e., the absolute biofilm roughness) but never impacted more than 80% of the mean biofilm thickness due to the highly cohesive basal layer. Anoxic biofilms were smoother and thinner than aerobic biofilms and thus associated with the detachment of smaller particles. Our results contradict the simplifying assumption of surface detachment that is considered in many biofilm models and suggest that discrete volume events should be considered

Human rights and the Ukraine War.

In this webinar, Paul Arnell and Carole Lyons (both affiliated with Robert Gordon University) discsuss the war in Ukraine from the Council of Europe perspective, focusing particularly on the human rights dimension. Specifically: what does the exclusion of Russia from the Council of Europe (on 16 March 2022) mean for the future of human rights in Europe

Production, purification and crystallization of a trans-sialidase from Trypanosoma vivax

Sialidases and trans-sialidases play important roles in the life cycles of various microorganisms. These enzymes can serve nutritional purposes, act as virulence factors or mediate cellular interactions (cell evasion and invasion). In the case of the protozoan parasite Trypanosoma vivax, trans-sialidase activity has been suggested to be involved in infection-associated anaemia, which is the major pathology in the disease nagana. The physiological role of trypanosomal trans-sialidases in host-parasite interaction as well as their structures remain obscure. Here, the production, purification and crystallization of a recombinant version of T. vivaxtrans-sialidase 1 (rTvTS1) are described. The obtained rTvTS1 crystals diffracted to a resolution of 2.5 angstrom and belonged to the orthorhombic space group P2(1)2(1)2(1), with unit-cell parameters a = 57.3, b = 78.4, c = 209.0 angstrom

A Practical Approach to Determining When to expand and When to Stabilize

A  successful  young  firm  experiencing  rapid  sales  growth   can  suddenly   encounter   declining profits  due  to  decreasing  contribution  margins   because   of   production   capacity   limitations. Expansion  is  not  an  automatic  solution  because  it  increases  fixed  costs  and  raises  the  first breakeven point . This paper is designed to provide strategies for  planning for  the combined  effects fixed costs, variable costs, revenues and sales will have on profits if additional  sales  growth  is attempted .   Rapidly   increasing   variable  production    costs  signal   the  need  to  consider  expansion, but product demand strength and life cycle stage affect the decision. Either of these can be respon­ sible for  declining contribution margins resulting  in  lower than anticipated  profits  at higher sales levels . Because of  higher fixed  costs  caused  by  expansion ,  the  business  cannot  return  to  sales levels  that  were  profitable   before  the  expansion. Why is it possible for a prosperous small business experiencing rapid sales growth to begin encountering declining profits even  though  sales  continue  to  increase?  Traditional  breakeven analysis illustrated in Exhibit I implies a path of "smooth sailing" once a firm is able to generate sufficient volume to reach the  critical "breakeven" hurdle. In fact, this  concept  has  been  a major source of deception because it implies that the only requirement for an increase in  profits  is  an increase  in  sales. Unfortunately, the inexperienced entrepreneur tends to view the sales volume/profit relationship in this simplistic manner, forgetting about two key limitations of linear breakeven analysis. Total revenue is depicted as a straight line based on the assumption that prices of products sold do not change regardless of volume, while total cost is shown as a straight line based on the assumption that variable cost per unit sold is constant and is not affected by the level of sales (11 )

The RNA-binding protein HuR contributes to neuroinflammation by promoting C-C chemokine receptor 6 (CCR6) expression on Th17 cells.

In both multiple sclerosis and experimental autoimmune encephalomyelitis (EAE), the C-C chemokine receptor 6 (CCR6) is critical for pathogenic T helper 17 (Th17) cell migration to the central nervous system (CNS). Whereas many cytokines and their receptors are potently regulated via post-transcriptional mechanisms in response to various stimuli, how CCR6 expression is post-transcriptionally regulated in Th17 cells is unknown. Here, using RNA-binding protein HuR conditional knock-out (KO) and wild-type (WT) mice, we present evidence that HuR post-transcriptionally regulates CCR6 expression by binding to and stabilizing Ccr6 mRNA and by promoting CCR6 translation. We also found that HuR down-regulates several microRNA expressions, which could target the 3\u27-UTR of Ccr6 mRNA for decay. Accordingly, knock-out of HuR reduced CCR6 expression on Th17 cells and impaired their migration to CNS compared with the response of WT Th17 cells and thereby ameliorated EAE. Together, these findings highlight how HuR contributes to Th17 cell-mediated autoimmune neuroinflammation and support the notion that targeting HuR might be a potential therapeutic intervention for managing autoimmune disorders of the CNS

Evaluating FAIR Digital Object and Linked Data as distributed object systems

FAIR Digital Object (FDO) is an emerging concept that is highlighted by European Open Science Cloud (EOSC) as a potential candidate for building a ecosystem of machine-actionable research outputs. In this work we systematically evaluate FDO and its implementations as a global distributed object system, by using five different conceptual frameworks that cover interoperability, middleware, FAIR principles, EOSC requirements and FDO guidelines themself. We compare the FDO approach with established Linked Data practices and the existing Web architecture, and provide a brief history of the Semantic Web while discussing why these technologies may have been difficult to adopt for FDO purposes. We conclude with recommendations for both Linked Data and FDO communities to further their adaptation and alignment.Comment: 40 pages, submitted to PeerJ C