A mixture of coal wash and fly ash as a pavement substructure material

The reuse of waste materials in engineering projects has become the subject of many research efforts worldwide as it provides economical as well as environmental benefits. Coal wash (CW) and fly ash (FA) are example waste materials that can be used as alternative aggregates in transportation infrastructure projects, specifically as base and subbase materials in roads. Class C FA has been extensively used as a stabilizing material due to its hardening potential. However, Class F fly ash, a non-pozzolanic material when used alone, has not been considered in past research projects. In this study, Class F fly ash is mixed with coal wash as a void filler to enhance its compaction efficiency and produce a compact and well interlocked structure. A laboratory testing plan is performed to assess the geotechnical properties of the mixtures with 0%, 7%, 10% and 13% FA content and it includes compaction tests, unconfined compressive strength tests, California Bearing Ratio (CBR) tests, collapse potential tests and permeability tests. The mixture with 7% FA is selected as the optimum mixture and its potential for tensile cracking under service loads is further investigated using four-point bending tests. Also, the resilient modulus and permanent deformations of the mixture are evaluated under different dry-back conditions using multistage repeated load triaxial tests

Behaviour of a Mixture of Coal Wash and Rubber Crumbs under Cyclic Loading

The interest in the utilization of granular waste materials as construction fills in lieu of quarried natural aggregates has been increasing recently, resulting in more sustainable and cost-effective industry practices being adopted. This study proposes a mixture of coal wash (CW; a by-product of coal mining) and rubber crumbs (RC; shredding of waste rubber tires) as a potential capping composite for railways. A series of cyclic triaxial tests mimicking typical rail traffic loads were conducted on CWRC mixtures with and without rest periods to gain an insightful understanding of the deformation mechanism of rubber particles. It is found that the inclusion of RC increases the axial permanent strain, the volumetric strain, and the damping ratio, and it reduces the resilient modulus, the shear modulus, and the breakage index (BI). Also, it is found that the mixture with RC recovers part of its energy dissipation efficiency after a rest period is applied, reducing the breakage index further even when the number of load cycles increases. Accordingly, a modified equation is proposed to determine the void ratio, capturing the deformation of the rubber

Recycled materials in railroad substructure: an energy perspective

Given that the current ballasted tracks in Australia may not be able to support faster and significantly heavier freight trains as planned for the future, the imminent need for innovative and sustainable ballasted tracks for transport infrastructure is crucial. Over the past two decades, a number of studies have been conducted by the researchers of Transport Research Centre (TRC) at the University of Technology Sydney (UTS) to investigate the ability of recycled rubber mats, as well as waste tyre cells and granulated rubber to improve the stability of track substructure including ballast and subballast layers. This paper reviews four applications of these novel methods, including using recycled rubber products such as CWRC mixtures (i.e., mixtures of coal wash (CW) and rubber crumbs (RC)) and SEAL mixtures (i.e., mixtures of steel furnace slag, CW and RC) to replace subballast/capping materials, tyre cells reinforcements for subballast/capping layer and under ballast mats; and investigates the energy dissipation capacity for each application based on small-scale cyclic triaxial tests and large-scale track model tests. It has been found that the inclusion of these rubber products increases the energy dissipation effect of the track, hence reducing the ballast degradation efficiently and increasing the track stability. Moreover, a rheological model is also proposed to investigate the effect of different rubber inclusions on their efficiency to reduce the transient motion of rail track under dynamic loading. The outcomes elucidated in this paper will lead to a better understanding of the performance of ballast tracks upgraded with resilient rubber products, while promoting environmentally sustainable and more affordable ballasted tracks for greater passenger comfort and increased safety

The role of clathrin in post-golgi trafficking in toxoplasma gondii

Apicomplexan parasites are single eukaryotic cells with a highly polarised secretory system that contains unique secretory organelles (micronemes and rhoptries) that are required for host cell invasion. In contrast, the role of the endosomal system is poorly understood in these parasites. With many typical endocytic factors missing, we speculated that endocytosis depends exclusively on a clathrin-mediated mechanism. Intriguingly, in Toxoplasma gondii we were only able to observe the endogenous clathrin heavy chain 1 (CHC1) at the Golgi, but not at the parasite surface. For the functional characterisation of Toxoplasma gondii CHC1 we generated parasite mutants conditionally expressing the dominant negative clathrin Hub fragment and demonstrate that CHC1 is essential for vesicle formation at the trans-Golgi network. Consequently, the functional ablation of CHC1 results in Golgi aberrations, a block in the biogenesis of the unique secretory microneme and rhoptry organelles, and of the pellicle. However, we found no morphological evidence for clathrin mediating endocytosis in these parasites and speculate that they remodelled their vesicular trafficking system to adapt to an intracellular lifestyle

Managing chronic hepatitis B: A qualitative study exploring the perspectives of people living with chronic hepatitis B in Australia

<p>Abstract</p> <p>Background</p> <p>The implementation of a comprehensive public health response to hepatitis B in Australia is urgently required to reduce the increasing burden of hepatitis B infection on the health system and the community. A significant gap in the public health response to hepatitis B is an understanding of how people with chronic hepatitis B (CHB) respond to CHB.</p> <p>Findings</p> <p>A qualitative study involving semi-structured interviews and focus group discussions was conducted. Interviews were held with 20 people with CHB from three states of Australia. In addition, four focus group discussions were held with a total of 40 community and health workers from culturally and linguistically diverse communities in four Australian states.</p> <p>People with CHB reported no formal or informal pre or post test discussion with little information about hepatitis B provided at the point of diagnosis. Knowledge deficits about hepatitis B were found among most participants. Few resources are available for people with CHB or their families to assist them in understanding the infection and promoting their health and well-being. A lack of confidence in the professional knowledge of service providers was noted throughout interviews.</p> <p>Conclusions</p> <p>People with CHB need culturally and linguistically appropriate education and information, particularly at the point of diagnosis. Primary health care professionals need the knowledge, skills and motivation to provide appropriate information to people with CHB, to ensure they have the capacity to better manage their infection.</p

Autophagy Protein Atg3 is Essential for Maintaining Mitochondrial Integrity and for Normal Intracellular Development of Toxoplasma gondii Tachyzoites

Autophagy is a cellular process that is highly conserved among eukaryotes and permits the degradation of cellular material. Autophagy is involved in multiple survival-promoting processes. It not only facilitates the maintenance of cell homeostasis by degrading long-lived proteins and damaged organelles, but it also plays a role in cell differentiation and cell development. Equally important is its function for survival in stress-related conditions such as recycling of proteins and organelles during nutrient starvation. Protozoan parasites have complex life cycles and face dramatically changing environmental conditions; whether autophagy represents a critical coping mechanism throughout these changes remains poorly documented. To investigate this in Toxoplasma gondii, we have used TgAtg8 as an autophagosome marker and showed that autophagy and the associated cellular machinery are present and functional in the parasite. In extracellular T. gondii tachyzoites, autophagosomes were induced in response to amino acid starvation, but they could also be observed in culture during the normal intracellular development of the parasites. Moreover, we generated a conditional T. gondii mutant lacking the orthologue of Atg3, a key autophagy protein. TgAtg3-depleted parasites were unable to regulate the conjugation of TgAtg8 to the autophagosomal membrane. The mutant parasites also exhibited a pronounced fragmentation of their mitochondrion and a drastic growth phenotype. Overall, our results show that TgAtg3-dependent autophagy might be regulating mitochondrial homeostasis during cell division and is essential for the normal development of T. gondii tachyzoites

A Polarised Population of Dynamic Microtubules Mediates Homeostatic Length Control in Animal Cells

An analysis of cells grown on micro-patterned lines, and of cells during zebrafish development, identifies a population of microtubules that align along the long axis of cells to mediate homeostatic length control

A Systematic Screen to Discover and Analyze Apicoplast Proteins Identifies a Conserved and Essential Protein Import Factor

Parasites of the phylum Apicomplexa cause diseases that impact global health and economy. These unicellular eukaryotes possess a relict plastid, the apicoplast, which is an essential organelle and a validated drug target. However, much of its biology remains poorly understood, in particular its elaborate compartmentalization: four membranes defining four different spaces. Only a small number of organellar proteins have been identified in particular few proteins are known for non-luminal apicoplast compartments. We hypothesized that enlarging the catalogue of apicoplast proteins will contribute toward identifying new organellar functions and expand the realm of targets beyond a limited set of characterized pathways. We developed a bioinformatic screen based on mRNA abundance over the cell cycle and on phyletic distribution. We experimentally assessed 57 genes, and of 30 successful epitope tagged candidates eleven novel apicoplast proteins were identified. Of those, seven appear to target to the lumen of the organelle, and four localize to peripheral compartments. To address their function we then developed a robust system for the construction of conditional mutants via a promoter replacement strategy. We confirm the feasibility of this system by establishing conditional mutants for two selected genes – a luminal and a peripheral apicoplast protein. The latter is particularly intriguing as it encodes a hypothetical protein that is conserved in and unique to Apicomplexan parasites and other related organisms that maintain a red algal endosymbiont. Our studies suggest that this peripheral plastid protein, PPP1, is likely localized to the periplastid compartment. Conditional disruption of PPP1 demonstrated that it is essential for parasite survival. Phenotypic analysis of this mutant is consistent with a role of the PPP1 protein in apicoplast biogenesis, specifically in import of nuclear-encoded proteins into the organelle

Blood transfusion during radical chemo-radiotherapy does not reduce tumour hypoxia in squamous cell cancer of the head and neck.

Background Patients with head and neck squamous cell carcinoma (HNSCC) undergoing radical chemo-radiation (CRT) frequently receive transfusion with packed red cells (PRCT) during radiotherapy on the basis that PRCT increases tumour oxygenation and overcomes hypoxia-induced radio-resistance. This is likely to be a significant oversimplification given the fact that tumour hypoxia is the result of several intrinsic and extrinsic factors, including many that are not directly related to serum haemoglobin (Hb). Therefore, we have studied the effect of PRCT on tumour oxygenation in a prospective cohort of patients who developed low Hb during radical CRT for HNSCC.Methods This was a prospective study of 20 patients with HNSCC receiving radical CRT undergoing PRCT for Hb-1. Patients underwent pretransfusion and posttransfusion intrinsic susceptibility-weighted (SWI) MRI and dynamic contrast-enhanced (DCE) MRI. Blood samples were obtained at the time of MRI scanning and two further time points for measuring Hb and a panel of serum cytokine markers of tumour hypoxia. 3D T2* and Ktrans maps were calculated from the MRI data for primary tumours and cervical lymph node metastases.Results PRCT produced no change (11 patients) or reduced (1 patient) T2* (tumour oxygenation) in 12 of the 16 (75%) evaluable primary tumours. Three of the four patients with improved tumour oxygenation progressed or had partial response following treatment completion. There were variable changes in Ktrans (tumour perfusion or vessel permeability) following PRCT that were of small magnitude for most tumours. Pre- and Post-PRCT levels of measured cytokines were not significantly different.Conclusions This study suggests that PRCT during radical CRT for HNSCC does not improve tumour oxygenation. Therefore, oncologists should consider changing practice according to NICE and American Association of Blood Banks guidelines on PRCT for anaemia