Effect of the displacement rate and inclination angle in steel fiber pullout tests

This paper summarizes the results obtained in an experimental campaign on the effect of the displacement pullout rate and the inclination angle of the steel fiber pullout tests. For that purpose, specimens were obtained from a self-compacting concrete with a compressive strength of 86 MPa. In the experimental program, hooked-end steel fibers of 0.75 mm diameter and 60 mm length were used. Tests were executed with both hooked-end fibers, and smooth fibers obtained from the former by cutting the hooked end. For both type of fibers, their embedment length into concrete was 20 mm, and the influence of fiber inclination angle toward the load direction was investigated by adopting values of 0∘, 30∘ and 60∘. The tests were performed at displacement rates of 0.01, 0.1 and 1 mm/s. The results have shown that the peak pullout load increased with the inclination angle, in particular for the smooth series. Furthermore, higher displacement rates led to a higher energy absorption capacity for the pullout of the smooth fibers, while the energy absorption remained almost stable for hooked-end fibers.project BIA2015-68678-C2-1-R. M. Tarifa appreciates the financial support from the Department of Applied Mechanics and Project Engineering, UCLM (2018), and from the Programa propio de I+D+i de la Universidad Politécnica de Madrid para realizar estancias de investigación internacional igual o superior a un mes (2019), to do two stays at the University of Minho, Guimarães, Portugal. E. Poveda acknowledges the funding from the International Campus of Excellence CYTEMA and the University of Castilla-La Mancha, throughout Ayudas para estancias en universidades y centros de investigación en el extranjero en 2019 en el ámbito del plan propio de investigación susceptibles de cofinanciación por el Fondo Europeo de Desarrollo Regional (FEDER), Programa 010100021 to fund her stays in the University of Minho during 2018 and 2019, respectively. The authors thank the support of the Department of Civil Engineering and the Laboratory of the Structural Division (LEST), University of Minh

Peptide nanofiber scaffolds for multipotent stromal cell culturing

Self-assembled peptide nanofibers are versatile materials providing suitable platforms for regenerative medicine applications. This chapter describes the use of peptide nanofibers as extracellular matrix mimetic scaffolds for two-dimensional (2D) and three-dimensional (3D) multipotent stromal cell culture systems and procedures for in vitro experiments using these scaffolds. Preparation of 2D and 3D peptide nanofiber scaffolds and cell culturing procedures are presented as part of in vitro experiments including cell adhesion, viability, and spreading analysis. Analysis of cellular differentiation on peptide nanofiber scaffolds is described through immunocytochemistry, qRT-PCR, and other biochemical experiments towards osteogenic and chondrogenic lineage. © Springer Science+Business Media New York 2013

The phylogenetically-related pattern recognition receptors EFR and XA21 recruit similar immune signaling components in monocots and dicots

During plant immunity, surface-localized pattern recognition receptors (PRRs) recognize pathogen-associated molecular patterns (PAMPs). The transfer of PRRs between plant species is a promising strategy for engineering broad-spectrum disease resistance. Thus, there is a great interest in understanding the mechanisms of PRR-mediated resistance across different plant species. Two well-characterized plant PRRs are the leucine-rich repeat receptor kinases (LRR-RKs) EFR and XA21 from Arabidopsis thaliana (Arabidopsis) and rice, respectively. Interestingly, despite being evolutionary distant, EFR and XA21 are phylogenetically closely related and are both members of the sub-family XII of LRR-RKs that contains numerous potential PRRs. Here, we compared the ability of these related PRRs to engage immune signaling across the monocots-dicots taxonomic divide. Using chimera between Arabidopsis EFR and rice XA21, we show that the kinase domain of the rice XA21 is functional in triggering elf18-induced signaling and quantitative immunity to the bacteria Pseudomonas syringae pv. tomato (Pto) DC3000 and Agrobacterium tumefaciens in Arabidopsis. Furthermore, the EFR:XA21 chimera associates dynamically in a ligand-dependent manner with known components of the EFR complex. Conversely, EFR associates with Arabidopsis orthologues of rice XA21-interacting proteins, which appear to be involved in EFR-mediated signaling and immunity in Arabidopsis. Our work indicates the overall functional conservation of immune components acting downstream of distinct LRR-RK-type PRRs between monocots and dicots

The Recognition of N-Glycans by the Lectin ArtinM Mediates Cell Death of a Human Myeloid Leukemia Cell Line

ArtinM, a d-mannose-binding lectin from Artocarpus heterophyllus (jackfruit), interacts with N-glycosylated receptors on the surface of several cells of hematopoietic origin, triggering cell migration, degranulation, and cytokine release. Because malignant transformation is often associated with altered expression of cell surface glycans, we evaluated the interaction of ArtinM with human myelocytic leukemia cells and investigated cellular responses to lectin binding. The intensity of ArtinM binding varied across 3 leukemia cell lines: NB4>K562>U937. The binding, which was directly related to cell growth suppression, was inhibited in the presence of Manα1-3(Manα1-6)Manβ1, and was reverted in underglycosylated NB4 cells. ArtinM interaction with NB4 cells induced cell death (IC50 = 10 µg/mL), as indicated by cell surface exposure of phosphatidylserine and disruption of mitochondrial membrane potential unassociated with caspase activation or DNA fragmentation. Moreover, ArtinM treatment of NB4 cells strongly induced reactive oxygen species generation and autophagy, as indicated by the detection of acidic vesicular organelles in the treated cells. NB4 cell death was attributed to ArtinM recognition of the trimannosyl core of N-glycans containing a ß1,6-GlcNAc branch linked to α1,6-mannose. This modification correlated with higher levels of N-acetylglucosaminyltransferase V transcripts in NB4 cells than in K562 or U937 cells. Our results provide new insights into the potential of N-glycans containing a β1,6-GlcNAc branch linked to α1,6-mannose as a novel target for anti-leukemia treatment