Fresh state properties of concrete incorporating scrap tire rubber

The purpose of this work is to study fresh lightweight concrete containing recycled tire rubber aggregates. An experiment on concrete obtained by incorporating rubber aggregate with a ratio replacement of 5, 7.5 and 10% is done to evaluate the effect of these aggregates on the workability of two sets of concrete specimens. In the first set, coarse aggregates were replaced by different percentages by weight of granulate rubber and in the second set both coarse aggregates and sand were replaced rubber granulate and crumb rubber. Density, air content, compaction and slump tests are performed on the seven mixtures. Taking into account the density and water absorption differences between the natural aggregates and the rubber aggregates, the validity of the tests results are discussed. The results show that incorporating these rubber aggregates affects most rheological properties of lightweight concrete, for some application of concrete incorporating waste tire, rubber particles should be treated.info:eu-repo/semantics/publishedVersio

Munc 18-1 Protein Molecules Move between Membrane Molecular Depots Distinct from Vesicle Docking Sites

Four evolutionarily conserved proteins are required for mammalian regulated exocytosis: three SNARE proteins, syntaxin, SNAP-25, and synaptobrevin, and the SM protein, Munc18-1. Here, using single-molecule imaging, we measured the spatial distribution of large cohorts of single Munc18-1 molecules correlated with the positions of single secretory vesicles in a functionally rescued Munc18-1-null cellular model. Munc18-1 molecules were nonrandomly distributed across the plasma membrane in a manner not directed by mode of interaction with syntaxin1, with a small mean number of molecules observed to reside under membrane resident vesicles. Surprisingly, we found that the majority of vesicles in fully secretion-competent cells had no Munc18-1 associated within distances relevant to plasma membrane-vesicle SNARE interactions. Live cell imaging of Munc18-1 molecule dynamics revealed that the density of Munc18-1 molecules at the plasma membrane anticorrelated with molecular speed, with single Munc18-1 molecules displaying directed motion between membrane hotspots enriched in syntaxin1a. Our findings demonstrate that Munc18-1 molecules move between membrane depots distinct from vesicle morphological docking sites

Analysis of Familial Hemophagocytic Lymphohistiocytosis type 4 (FHL-4) mutant proteins reveals that S-acylation is required for the function of syntaxin 11 in natural killer cells

Natural killer (NK) cell secretory lysosome exocytosis and cytotoxicity are impaired in familial hemophagocytic lymphohistiocytosis type 4 (FHL-4), a disorder caused by mutations in the gene encoding the SNARE protein syntaxin 11. We show that syntaxin 11 binds to SNAP23 in NK cells and that this interaction is reduced by FHL-4 truncation and frameshift mutation proteins that delete all or part of the SNARE domain of syntaxin 11. In contrast the FHL-4 mutant proteins bound to the Sec-1/Munc18-like (SM) protein Munc18-2. We demonstrate that the C-terminal cysteine rich region of syntaxin 11, which is deleted in the FHL-4 mutants, is S-acylated. This posttranslational modification is required for the membrane association of syntaxin 11 and for its polarization to the immunological synapse in NK cells conjugated to target cells. Moreover, we show that Munc18-2 is recruited by syntaxin 11 to intracellular membranes in resting NK cells and to the immunological synapse in activated NK cells. This recruitment of Munc18-2 is abolished by deletion of the C-terminal cysteine rich region of syntaxin 11. These results suggest a pivotal role for S-acylation in the function of syntaxin 11 in NK cells

Dimethyl fumarate in patients admitted to hospital with COVID-19 (RECOVERY): a randomised, controlled, open-label, platform trial

Dimethyl fumarate (DMF) inhibits inflammasome-mediated inflammation and has been proposed as a treatment for patients hospitalised with COVID-19. This randomised, controlled, open-label platform trial (Randomised Evaluation of COVID-19 Therapy [RECOVERY]), is assessing multiple treatments in patients hospitalised for COVID-19 (NCT04381936, ISRCTN50189673). In this assessment of DMF performed at 27 UK hospitals, adults were randomly allocated (1:1) to either usual standard of care alone or usual standard of care plus DMF. The primary outcome was clinical status on day 5 measured on a seven-point ordinal scale. Secondary outcomes were time to sustained improvement in clinical status, time to discharge, day 5 peripheral blood oxygenation, day 5 C-reactive protein, and improvement in day 10 clinical status. Between 2 March 2021 and 18 November 2021, 713 patients were enroled in the DMF evaluation, of whom 356 were randomly allocated to receive usual care plus DMF, and 357 to usual care alone. 95% of patients received corticosteroids as part of routine care. There was no evidence of a beneficial effect of DMF on clinical status at day 5 (common odds ratio of unfavourable outcome 1.12; 95% CI 0.86-1.47; p = 0.40). There was no significant effect of DMF on any secondary outcome

Dimethyl fumarate in patients admitted to hospital with COVID-19 (RECOVERY): a randomised, controlled, open-label, platform trial

Dimethyl fumarate (DMF) inhibits inflammasome-mediated inflammation and has been proposed as a treatment for patients hospitalised with COVID-19. This randomised, controlled, open-label platform trial (Randomised Evaluation of COVID-19 Therapy [RECOVERY]), is assessing multiple treatments in patients hospitalised for COVID-19 (NCT04381936, ISRCTN50189673). In this assessment of DMF performed at 27 UK hospitals, adults were randomly allocated (1:1) to either usual standard of care alone or usual standard of care plus DMF. The primary outcome was clinical status on day 5 measured on a seven-point ordinal scale. Secondary outcomes were time to sustained improvement in clinical status, time to discharge, day 5 peripheral blood oxygenation, day 5 C-reactive protein, and improvement in day 10 clinical status. Between 2 March 2021 and 18 November 2021, 713 patients were enroled in the DMF evaluation, of whom 356 were randomly allocated to receive usual care plus DMF, and 357 to usual care alone. 95% of patients received corticosteroids as part of routine care. There was no evidence of a beneficial effect of DMF on clinical status at day 5 (common odds ratio of unfavourable outcome 1.12; 95% CI 0.86-1.47; p = 0.40). There was no significant effect of DMF on any secondary outcome

Durability properties of five years aged lightweight concretes containing rubber aggregates

Scrap tyres are one of the most important wastes. They can be used in different ways because of their availability and their non-degradable nature. This paper aims to demonstrate their reuse through durability properties experimental assessment of lightweight concretes aged five years, incorporating rubber aggregates as partial replacement of 5%, 7.5% and 10% of coarse/fine and coarse aggregates. The effect of the rubber aggregates on the lightweight concretes durability has been analysed. Firstly, the water absorption was evaluated, and then the mass losses were measured through many tests: freeze-thaw, elevated temperature and attack by Na2SO4 and HCl solutions. Wetting-drying cycles were carried out in order to accelerate the aging of the studied lightweight concretes and to reduce the tests duration. It has been observed that the water absorption decreased with small rubber content. The mass losses of the mixes were almost depending on rubber aggregates content and size, and the exposures duration.info:eu-repo/semantics/publishedVersio

Life cycle assessment of concrete incorporating scrap tire rubber: comparative study

At present, the environment suffers from two major problems, the first is the adverse effect of the production of the construction materials due to the resulting emissions and the second one is the increase of the consumption of the natural materials needed in the construction industry. There are interesting waste products such as the used tires that can be a resource of those materials to replace the natural resources in depletion. The use of scrap tire rubber to produce concrete in Algeria is not really an available technique. A life cycle assessment to compare an ordinary cement Portland concrete (Cref) and six rubberized concretes (CRm) and (CRg) from the environmental impact was carried out using ATHENA Estimator. The nine studied environmental impact categories are Climate change, Acidification potential, particulate matters, Eutrophication, Destruction of the stratospheric ozone layer, Photochemical ozone creation, Primary energy consumption, Consumption of fossil fuels, and Cumulative energy demand. The results inter-compared show that the energy demand and the generated emissions in the case of ordinary concrete are superiors than those of the rubberized concretes; concretes made with natural aggregates and 5, 7.5 and 10% of crumb rubber and coarse rubber aggregates (CRm) are more environmentally friendly than (CRg) mixtures made with natural aggregates and 5, 7.5 and 10% of coarse rubber aggregates. It is also concluded that the environmental impacts depend on the amount of substituted aggregates

Shear Force in Bolted Connection Due to Traffic and Temperature Loads in Hybrid Steel-FRP Bridges

As many bridges are reaching the end of their service life, researchers are searching for new solutions to extend the lifespan of those bridges. Fibre reinforce polymers (FRP) could be possible a solution for bridges with deck problems. Lightweight FRP decks can be installed quickly via bolted connectors on steel substructure. In general, shear force in the connector is not taken into account during the design of FRP decks because slip behaviour and interaction with steel substructure is unknown. This research connects to research at TU Delft on non-slip shear connectors for FRP decks. Aim of this paper is to quantify shear forces in bolted connectors due to traffic and temperature loads. The direction of webs, fibres in panel facings and the expansion coefficient of resin has been investigated to determine the influence of the FRP deck on the shear force in the connectors. To investigate the results of traffic loading and temperature loading on real bridges, a database of bridges in the Netherlands has been used. Results from the analyses offer an indication of the influence of the laminates on the shear force in the connectors and show shear force ranges that can occur in existing bridges.</p