Self-stresses and Crack Formation by Particle Swelling in Cohesive Granular Media

We present a molecular dynamics study of force patterns, tensile strength and crack formation in a cohesive granular model where the particles are subjected to swelling or shrinkage gradients. Non-uniform particle size change generates self-equilibrated forces that lead to crack initiation as soon as strongest tensile contacts begin to fail. We find that the coarse-grained stresses are correctly predicted by an elastic model that incorporates particle size change as metric evolution. The tensile strength is found to be well below the theoretical strength as a result of inhomogeneous force transmission in granular media. The cracks propagate either inward from the edge upon shrinkage and outward from the center upon swelling

Gender impacts on rural cycling decisions : a case study of Bugesera district, Rwanda

Papers presented virtually at the 41st International Southern African Transport Conference on 10-13 July 2034In recent years, cycling mobility has attracted increasing interest from researchers. However, most available data on bicycling has focused on transport planning and policy development to address urban-related issues related. Only some studies have sought to understand rural cyclists' daily mobility decisions. The Global Positioning System (GPS) is an innovative tool that addresses spatial differences, even from a gender perspective. The study, therefore, assesses the impact of men's and women's cycling decisions in rural communities of low-income countries. The study targeted bike taxi customers and owners. Fifty participants of different gender, social background and occupation were recruited and handed a GPS device to collect their travel tracks in Nyamata and Mayange, Bugesera, Rwanda. Tracks collected contained road network data, distance (Origin-Destination), Elevation and Speed. Additional information was obtained through a survey, Focus Group Discussions and mapping of participants' daily activities. Limited gender inequality between male and female cyclists confirms that travelling speed has no impact on cycling decisions, reinforcing the notion that cultural norms and the lack of bicycle education, among many others, are the main barriers to more female cycling in Sub-Saharan Africa. Creating policies that encourage bicycle education at the school level, and teaching the value of cycling use for health and the environment, will help destigmatize cycling and remove cultural norms and restrictions

Hepatitis B Virus Impairs TLR9 Expression and Function in Plasmacytoid Dendritic Cells

Plasmacytoid dendritic cells (pDCs) play a key role in detecting pathogens by producing large amounts of type I interferon (IFN) by sensing the presence of viral infections through the Toll-Like Receptor (TLR) pathway. TLR9 is a sensor of viral and bacterial DNA motifs and activates the IRF7 transcription factor which leads to type I IFN secretion by pDCs. However, during chronic hepatitis B virus (HBV) infection, pDCs display an impaired ability to secrete IFN-α following ex vivo stimulation with TLR9 ligands. Here we highlight several strategies used by HBV to block IFN-α production through a specific impairment of the TLR9 signaling. Our results show that HBV particle internalisation could inhibit TLR9- but not TLR7-mediated secretion of IFN-α by pDCs. We observed that HBV down-regulated TLR9 transcriptional activity in pDCs and B cells in which TLR9 mRNA and protein levels were reduced. HBV can interfere with TLR9 activity by blocking the MyD88-IRAK4 axis and Sendai virus targeting IRF7 to block IFN-α production. Neutralising CpG motif sequences were identified within HBV DNA genome of genotypes A to H which displayed a suppressive effect on TLR9-immune activation. Moreover, TLR9 mRNA and protein were downregulated in PBMCs from patients with HBV-associated chronic hepatitis and hepatocellular carcinoma. Thus HBV has developed several escape mechanisms to avoid TLR9 activation in both pDCs and B lymphocytes, which may in turn contribute to the establishment and/or persistence of chronic infection

Range-reference determination of lymphocyte subsets in Moroccan blood donors

Background: Information on lymphocyte populations (T, B, and Natural killer cells) and subpopulations (CD4 and CD8) in Morocco is scarce if not inexistent. Objective: To establish a reference value of these cells in 242 Moroccan young adult blood donors by flow cytometry. Results: Smokers had significantly higher total leukocyte count (p < 0.001), total lymphocyte count (p < 0.0001) and higher CD3+CD4+ cells (p < 0.0001). The percentage of CD3-CD56+ subsets was affected by smoking (p < 0.01). Our analysis positively correlate with previous observations of an increase of absolute CD4+ T cells, with no changes in other lymphocyte subset cells in smokers. The lymphocyte subpopulation distributions for all antigens were found to be similar to those reported in Saudi and Italian adults, while higher levels were reported for the same gender in other countries, especially Ghana and Kuwait. Conclusion: The international classification standards of the HIV-infected subjects according to their rates of CD4 are applicable to the present study’s population

Pancreatic preneoplastic lesions plasma signatures and biomarkers based on proteome profiling of mouse models

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