MAT-758: CONSTRUCTABILITY BENEFITS OF THE USE OF LIGHTWEIGHT FOAMED CONCRETE FILL (LFCF) IN PAVEMENT APPLICATIONS

Lightweight Foamed Concrete Fill (LFCF), also known as cellular concrete, has been growing in use in transportation infrastructure projects over recent years. LFCF is a versatile construction material that has now been in use for over 30 years. A number of recent road rehabilitation projects have demonstrated some of the benefits of use. With a greater emphasis on sustainability on all provincial and municipal road projects, new solutions are being sought to minimize the generation of waste and deliver better performing pavements that require less maintenance interventions. Roads over peat and organic deposits pose challenges for road agencies. They are subject to continual and long term settlements that necessitate frequent patch repairs. The downside of such repairs is that the additional weight of the new asphalt, triggers further settlement. Traditionally, permanent solutions have necessitated the total reconstruction of the road section and removal of the underlying organic layers. This is expensive, creates huge traffic disruptions, generates waste and consumes large volumes of aggregate for the reinstatement. The use of lightweight fill offers an alternative as it allows the pavement to be ‘floated’ above the organic layer. However, the traditional lightweight materials, such as polystyrene, have been prohibitively expensive for such applications. In recent years, LFCF has been successfully used as a cost effective solution in road works. LFCF is a foamed, pumpable, cementitious fill with a density of only 475 kg/m3, about a quarter of that of conventional granular fill. With a compressive strength of at least 0.5 MPa, it has sufficient strength to support pavement loads. However, the real advantages relate to constructability, since the material can be installed very quickly, minimizes excavation time, can be placed in winter and does not require conventional compaction or associated testing. This paper will provide an overview of the use of LFCF for road works, including typical specifications, quality control/assurance requirements, and performance based on a number of case study applications

The Counterpart Principle of Analogical Support by Structural Similarity

We propose and investigate an Analogy Principle in the context of Unary Inductive Logic based on a notion of support by structural similarity which is often employed to motivate scientific conjectures

The environmental contaminant DDE fails to influence the outcome of sexual differentiation in the marine turtle Chelonia mydas.

In many turtles, the temperature experienced during the middle of egg incubation determines the sex of the offspring. The implication of steroid sex hormones as the proximate trigger for sex determination opens the possibility that endocrine-disrupting contaminants may also influence the outcome of sexual differentiation. In this study we investigate the potential effects of DDE (a common DDT metabolite) on sexual differentiation of Chelonia mydas (green sea turtle). Four clutches of eggs collected from Heron Island, Queensland, Australia, were treated with DDE at the beginning of the thermosensitive period for sexual determination. An incubation temperature of 28 degrees C or less produces male hatchlings in this species, whereas 30 degrees C or more produces female hatchlings. Dosed eggs were consequently incubated at two temperatures (27.6 degrees C and 30.4 degrees C) on the upper and lower boundaries of the sex determination threshold for this species. DDE, ranging from 3.3 to 66.5 microg, was dissolved in 5, 10, and 25 microl ethanol and applied to eggshells above the embryo. Less than 2.5 ng/g DDE was present in eggs prior to dosing. Approximately 34% of the applied DDE was absorbed in the eggs, but only approximately 8% of applied DDE was found in embryos. Thus, treated eggs, corrected for background DDE, had up to 543 ng/g DDE. The sex ratio at these doses did not differ from what would be expected on consideration of temperature alone. Incubation time, hatching success, incidence of body deformities, hatching size, and weight were also within the limits of healthy developed hatchlings. This indicates that the eggs of C. mydas in the wild with concentrations of DDE less than 543 ng/g should produce hatchlings with relatively high hatching success, survival rate, and normally differentiated gonads

Self-efficacy enhanced in a cross-cultural context through an initiative in under-resourced schools in KwaZulu-Natal, South Africa

This paper discusses the Khanyisa Programme, an initiative in KwaZulu-Natal, South Africa, where learners from under-resourced schools are supported by teachers and high achievers in Grade 11 and 12 from a previously advantaged state school under apartheid. A qualitative, evaluative study was undertaken to identify key elements in the ongoing success of the programme and collect participant suggestions for improvement. The findings, discussed within the framework of self-efficacy theory, identified enormous gains by Khanyisa learners, leading to vastly improved career prospects

Interventional Radiology and the Care of the Oncology Patient

Interventional Radiology (IR) is occupying an increasingly prominent role in the care of patients with cancer, with involvement from initial diagnosis, right through to minimally invasive treatment of the malignancy and its complications. Adequate diagnostic samples can be obtained under image guidance by percutaneous biopsy and needle aspiration in an accurate and minimally invasive manner. IR techniques may be used to place central venous access devices with well-established safety and efficacy. Therapeutic applications of IR in the oncology patient include local tumour treatments such as transarterial chemo-embolisation and radiofrequency ablation, as well as management of complications of malignancy such as pain, organ obstruction, and venous thrombosis

Expression of HIV receptors, alternate receptors and co-receptors on tonsillar epithelium: implications for HIV binding and primary oral infection

BACKGROUND: Primary HIV infection can develop from exposure to HIV in the oral cavity. In previous studies, we have documented rapid and extensive binding of HIV virions in seminal plasma to intact mucosal surfaces of the palatine tonsil and also found that virions readily penetrated beneath the tissue surfaces. As one approach to understand the molecular interactions that support HIV virion binding to human mucosal surfaces, we have examined the distribution of the primary HIV receptor CD4, the alternate HIV receptors heparan sulfate proteoglycan (HS) and galactosyl ceramide (GalCer) and the co-receptors CXCR4 and CCR5 in palatine tonsil. RESULTS: Only HS was widely expressed on the surface of stratified squamous epithelium. In contrast, HS, GalCer, CXCR4 and CCR5 were all expressed on the reticulated epithelium lining the tonsillar crypts. We have observed extensive variability, both across tissue sections from any tonsil and between tonsils, in the distribution of epithelial cells expressing either CXCR4 or CCR5 in the basal and suprabasal layers of stratified epithelium. The general expression patterns of CXCR4, CCR5 and HS were similar in palatine tonsil from children and adults (age range 3–20). We have also noted the presence of small clusters of lymphocytes, including CD4(+ )T cells within stratified epithelium and located precisely at the mucosal surfaces. CD4(+ )T cells in these locations would be immediately accessible to HIV virions. CONCLUSION: In total, the likelihood of oral HIV transmission will be determined by macro and micro tissue architecture, cell surface expression patterns of key molecules that may bind HIV and the specific properties of the infectious inoculum

Comparison of metal bioaccumulation in crop types and consumable parts between two growth periods

A high proportion of populations in most developing countries live below the poverty line and those near refuse grounds resort to dumpsite farming to grow food. Consequently, high levels of waste‐derived contaminants are found in crops consumed by these people. This study investigates the extent to which crops cultivated on the Mbale dumpsite (Uganda) were contaminated by 11 metals and 2 non‐metals: iron (Fe), aluminum (Al), zinc (Zn), manganese (Mn), copper (Cu), mercury (Hg), lead (Pb), nickel (Ni), cobalt (Co), cadmium (Cd), selenium (Se), chromium (Cr), and arsenic (As). We investigated how element bioaccumulation in crops was influenced by the growth period (short‐ and long‐term crop maturity). The short‐term crops were Zea mays and Amaranthus cruentus, whereas the long‐term crops were Manihot esculenta, Colocasia esculenta, Musa acuminata, Carica papaya, Coffea arabica, and Saccharum officinarum. Results showed that nine metals were present at concentrations above World Health Organization/Food and Agriculture Organization (WHO/FAO) food safety recommendations and hence may pose health risks to consumers. In this study, leaves contained higher metal concentrations than other analyzed consumable parts. Pb and Co were found at higher concentrations in leaves of short‐term crops than in long‐term crops. Among short‐term crops, only Z. mays seeds contained permissible metal concentrations by WHO/FAO standards. The growth period was also found to influence metal bioaccumulation in crop types. Pb, Co, Fe, Al, and Cu concentrations were significantly higher in the short‐term crops than in long‐term crops, while Mn, Ni, and Cr concentrations were higher in long‐term crops than in short‐term crops. Overall, public awareness about the health risks associated with consuming short‐term leafy crops grown on dumpsites should be improved to reduce toxic metal exposure. While implementing such a campaign, the food supply of individuals whose survival depends on such crops should not be jeopardized. Therefore, farmers need alternative farming areas outside dumpsites. Integr Environ Assess Manag 2022;18:1056–1071. © 2021 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC)

The effects of Tween-80 on the integrity of solutions of capsaicin: useful information for performing tussigenic challenges

ABSTRACT: BACKGROUND: Because variable results of capsaicin challenges may be due to the incomplete solubility of capsaicin, we sought to determine if the use of Tween-80 in solutions of capsaicin improves actual concentrations of freshly prepared and stored solutions. METHODS: Capsaicin solutions ranging from 0.5-128 muM were mixed with and without Tween-80. Samples of various concentrations were then stored under 4 environmental conditions: 4 degrees C, protected from light; room temperature, protected from light; room temperature, exposed to light; -20 degrees C. All samples were analyzed initially, and at 2 and 4 months. RESULTS: While freshly prepared solutions with Tween-80 had consistently higher concentrations than those prepared without Tween-80 (83% vs. 69%), Tween-80 does not facilitate complete solubility. For solutions stored at 4 degrees C and protected from light, there was a significant decrease after 2 months in low concentration solutions of both the Tween-80 and non-Tween-80 solutions. Both Tween-80 and non-Tween-80 containing solutions significantly decreased in concentration after 2 months when stored at room temperature and protected from light, room temperature and exposed to light, and -20 degrees C. Concentrations of solutions made of 4 muM or higher are stable when stored at 4 degrees C and protected from light for 4 months. CONCLUSION: While the inherent difficulty of forcing capsaicin into solution cannot be eliminated, it can be improved with Tween-80. However, the addition of Tween-80 does not prevent the breakdown of stored capsaicin solutions. We recommend preparing and storing capsaicin solutions according to the methods and results of this study

Mutation analysis of HIF prolyl hydroxylases (PHD/EGLN) in individuals with features of phaeochromocytoma and renal cell carcinoma susceptibility

Germline mutations in the von Hippel–Lindau disease (VHL) and succinate dehydrogenase subunit B (SDHB) genes can cause inherited phaeochromocytoma and/or renal cell carcinoma(RCC). Dysregulation of the hypoxia-inducible factor (HIF) transcription factors has been linked to VHL and SDHB-related RCC; both HIF dysregulation and disordered function of a prolyl hydroxylase domain isoform 3 (PHD3/EGLN3)-related pathway of neuronal apoptosis have been linked to the development of phaeochromocytoma. The 2-oxoglutarate-dependent prolyl hydroxylase enzymes PHD1 (EGLN2), PHD2 (EGLN1) and PHD3 (EGLN3) have a key role in regulating the stability of HIF-a subunits (and hence expression of the HIF-a transcription factors). A germline PHD2 mutation has been reported in association with congenital erythrocytosis and recurrent extra-adrenal phaeochromocytoma. We undertook mutation analysis of PHD1, PHD2 and PHD3 in two cohorts of patients with features of inherited phaeochromocytoma (nZ82) and inherited RCC (nZ64) and no evidence of germline mutations in known susceptibility genes. No confirmed pathogenic mutations were detected suggesting that mutations in these genes are not a frequent cause of inherited phaeochromocytoma or RCC