Ultrasonic, molecular and mechanical testing diagnostics in natural fibre reinforced, polymer-stabilised earth blocks

The aim of this research study was to evaluate the influence of utilising natural polymers as a form of soil stabilization, in order to assess their potential for use in building applications. Mixtures were stabilized with a natural polymer (alginate) and reinforced with wool fibres in order to improve the overall compressive and flexural strength of a series of composite materials. Ultrasonic pulse velocity (UPV) and mechanical strength testing techniques were then used to measure the porous properties of the manufactured natural polymer-soil composites, which were formed into earth blocks. Mechanical tests were carried out for three different clays which showed that the polymer increased the mechanical resistance of the samples to varying degrees, depending on the plasticity index of each soil. Variation in soil grain size distributions and Atterberg limits were assessed and chemical compositions were studied and compared. X-ray diffraction (XRD), X-ray fluorescence spectroscopy (XRF), and energy dispersive X-ray fluorescence (EDXRF) techniques were all used in conjunction with qualitative identification of the aggregates. Ultrasonic wave propagation was found to be a useful technique for assisting in the determination of soil shrinkage characteristics and fibre-soil adherence capacity and UPV results correlated well with the measured mechanical properties

A combination of SEM and EDX studies on a clay-based natural composite with animal fibre and its mechanical implications

A variety of natural fibres are nowadays being utilized as soil reinforcement. Test results demonstrate the positive effects of adding natural fibres to soils, in that they decrease shrinkage, reduce curing time and enhance compressive, flexural and shear strength if an optimum reinforcement ratio can be utilised. This paper describes a study which uses a Scanning Electron Microscope (SEM) and an Energy Diffraction Analysis of X-rays (EDX) technique on clay-based composites stabilized with natural polymer and fibres. Different dosages of fibres and several types of soils have been used in this study with the aim of determining advantageous properties for building material applications. SEM and EDX test results reveal the degree of bonding between the particles of soil and the natural fibers. This has enabled a better understanding of the micro-morphology of the natural fibers and their effect on the overall composite material structure. Microscopic analysis was combined with mechanical tests to establish the different strength characteristics of every soil

Ultrasonic, molecular and mechanical testing diagnostics in natural fibre reinforced, polymer-stabilised earth blocks

The aim of this research study was to evaluate the influence of utilising natural polymers as a form of soil stabilization, in order to assess their potential for use in building applications. Mixtures were stabilized with a natural polymer (alginate) and reinforced with wool fibres in order to improve the overall compressive and flexural strength of a series of composite materials. Ultrasonic pulse velocity (UPV) and mechanical strength testing techniques were then used to measure the porous properties of the manufactured natural polymer-soil composites, which were formed into earth blocks. Mechanical tests were carried out for three different clays which showed that the polymer increased the mechanical resistance of the samples to varying degrees, depending on the plasticity index of each soil. Variation in soil grain size distributions and Atterberg limits were assessed and chemical compositions were studied and compared. X-ray diffraction (XRD), X-ray fluorescence spectroscopy (XRF), and energy dispersive X-ray fluorescence (EDXRF) techniques were all used in conjunction with qualitative identification of the aggregates. Ultrasonic wave propagation was found to be a useful technique for assisting in the determination of soil shrinkage characteristics and fibre-soil adherence capacity and UPV results correlated well with the measured mechanical properties

Ultrasonic, Molecular and Mechanical Testing Diagnostics in Natural Fibre Reinforced, Polymer-Stabilized Earth Blocks

The aim of this research study was to evaluate the influence of utilising natural polymers as a form of soil stabilization, in order to assess their potential for use in building applications. Mixtures were stabilized with a natural polymer (alginate) and reinforced with wool fibres in order to improve the overall compressive and flexural strength of a series of composite materials. Ultrasonic pulse velocity (UPV) and mechanical strength testing techniques were then used to measure the porous properties of the manufactured natural polymer-soil composites, which were formed into earth blocks. Mechanical tests were carried out for three different clays which showed that the polymer increased the mechanical resistance of the samples to varying degrees, depending on the plasticity index of each soil. Variation in soil grain size distributions and Atterberg limits were assessed and chemical compositions were studied and compared. X-ray diffraction (XRD), X-ray fluorescence spectroscopy (XRF), and energy dispersive X-ray fluorescence (EDXRF) techniques were all used in conjunction with qualitative identification of the aggregates. Ultrasonic wave propagation was found to be a useful technique for assisting in the determination of soil shrinkage characteristics and fibre-soil adherence capacity and UPV results correlated well with the measured mechanical properties

An interview with Mayra Rivera: Postcolonial women's writing and material religion

In this interview, Mayra Rivera talks about her own journey with literature and theology and what this relationship means to her. She talks about the distinct role that literature plays in a postcolonial context, and its ability to articulate painful losses, histories, as well as economic and environmental realities, with a particular focus on the Caribbean and South America, and the work of Sylvia Wynter, Edwidge Danticat, Mayra Santos Febres, Édouard Glissant, amongst others. This storytelling is often deeply theological and material. The nature of this entanglement, between storytelling, theology, materiality, and post/neo/de-colonialism, is explored in heartfelt detail

IFNAR1-Signalling Obstructs ICOS-mediated Humoral Immunity during Non-lethal Blood-Stage Plasmodium Infection

Funding: This work was funded by a Career Development Fellowship (1028634) and a project grant (GRNT1028641) awarded to AHa by the Australian National Health & Medical Research Council (NHMRC). IS was supported by The University of Queensland Centennial and IPRS Scholarships. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Peer reviewedPublisher PD

The hypotensive effect of acute and chronic AMP-activated protein kinase activation in normal and hyperlipidemic mice

AMP-activated protein kinase (AMPK) is present in the arterial wall and is activated in response to cellular stressors that raise AMP relative to ADP/ATP. Activation of AMPK in vivo lowers blood pressure but the influence of hyperlipidemia on this response has not been studied. ApoE-/- mice on high fat diet for 6 weeks and age-matched controls were treated with the AMPK activator, AICAR daily for two weeks. Under anesthesia, the carotid artery was cannulated for blood pressure measurements. Aortic tissue was removed for in vitro functional experiments and AMPK activity was measured in artery homogenates by Western blotting. ApoE-/- mice had significantly raised mean arterial pressure; chronic AICAR treatment normalized this but had no effect in normolipidemic mice, whereas acute administration of AICAR lowered mean arterial pressure in both groups. Chronic AICAR treatment increased phosphorylation of AMPK and its downstream target acetyl-CoA carboxylase in normolipidemic but not ApoE-/- mice. In aortic rings, AMPK activation induced vasodilation and an anticontractile effect, which was attenuated in ApoE-/- mice. This study demonstrates that hyperlipidemia dysregulates the AMPK pathway in the arterial wall but this effect can be reversed by AMPK activation, possibly through improving vessel compliance

A study of the TNF/LTA/LTB locus and susceptibility to severe malaria in highland papuan children and adults

Background: Severe malaria (SM) syndromes caused by Plasmodium falciparum infection result in major morbidity and mortality each year. However, only a fraction of P. falciparum infections develop into SM, implicating host genetic factors as important determinants of disease outcome. Previous studies indicate that tumour necrosis factor (TNF) and lymphotoxin alpha (LT alpha) may be important for the development of cerebral malaria (CM) and other SM syndromes

α-Synuclein impairs macroautophagy: implications for Parkinson’s disease

α-Synuclein impairs autophagosome formation and mislocalizes Atg9 by inhibiting Rab1a

The Role of BACH2 in T Cells in Experimental Malaria Caused by Plasmodium chabaudi chabaudi AS

BTB and CNC Homology 1, Basic Leucine Zipper Transcription Factor 2 (BACH2) is a transcription factor best known for its role in B cell development. More recently, it has been associated with T cell functions in inflammatory diseases, and has been proposed as a master transcriptional regulator within the T cell compartment. In this study, we employed T cell-specific Bach2-deficient (B6.Bach2ΔT) mice to examine the role of this transcription factor in CD4+ T cell functions in vitro and in mice infected with Plasmodium chabaudi AS. We found that under CD4+ T cell polarizing conditions in vitro, Th2, and Th17 helper cell subsets were more active in the absence of Bach2 expression. In mice infected with P. chabaudi AS, although the absence of Bach2 expression by T cells had no effect on blood parasitemia or disease pathology, we found reduced expansion of CD4+ T cells in B6.Bach2ΔT mice, compared with littermate controls. Despite this reduction, we observed increased frequencies of Tbet+ IFNγ+ CD4+ (Th1) cells and IL-10-producing Th1 (Tr1) cells in mice lacking Bach2 expression by T cells. Studies in mixed bone marrow chimeric mice revealed T cell intrinsic effects of BACH2 on hematopoietic cell development, and in particular, the generation of CD4+ and CD8+ T cell subsets. Furthermore, T cell intrinsic BACH2 was needed for efficient expansion of CD4+ T cells during experimental malaria in this immunological setting. We also examined the response of B6.Bach2ΔT mice to a second protozoan parasitic challenge with Leishmania donovani and found similar effects on disease outcome and T cell responses. Together, our findings provide new insights into the role of BACH2 in CD4+ T cell activation during experimental malaria, and highlight an important role for this transcription factor in the development and expansion of T cells under homeostatic conditions, as well as establishing the composition of the effector CD4+ T cell compartment during infection