[en] The purpose of this study was threefold: to investigate the relationship between settleability and the physical properties of activated sludge, to correlate settleability and key operational parameters such as chemical oxygen demand (COD) concentration at the aeration basin inlet and to determine potential operational improvements to the Oakville Oil Refinery Wastewater Treatment Plant. Nine separate sets of stirred sludge-settling tests were conducted over a six-month period to measure settleability. The stirred sludge volume index (SSVI), the zone settling constants, and the Zheng-Bagley compression constants were determined. State point analyses were conducted to determine the maximum solids flux of the clarifiers. The concentrations of Al, Mn, Mg, Fe, Ca, Na, and K were determined to identify potential correlations to settling characteristics. Extracellular polymeric substances were extracted from the sludge and analyzed for the same reason. The performance of the clarifiers was highly variable during the period examined. As the refinery process flows and effluent streams changed, influent COD increased, from an average of 180mg/L to 600mg/L. Concurrently the settleability of the sludge decreased from excellent (SSVI = 68mL/g) to very poor (150mL/g), perhaps as the result of under aeration. State point analyses indicated that the clarifiers are under-sized for process upsets of this magnitude. (author)

[en] Mutation induction at the hypoxanthine-guanine phosphoribosyl transferase (hprt) locus has been studied in three human bladder tumour cell lines of varying radiosensitivity. U1-S40b, a radiosensitive mutant clone of MGH-U1, has been previously reported to show no difference in split-dose recovery or low dose-rate sparing, but to have an impaired repair fidelity when compared to its parent line. In this paper the authors show that U1-S40b is less mutable at the hprt locus at a similar level of survival. This may represent an increased incidence of severe or non-repairable lesions, making hprt^- mutants poorly recoverable in U1-S40b when compared to MGH-U1. No difference was seen in mutation induction between MGH-U1 and RT112, another human bladder tumour cell line of similar radiosensitivity to MGH-U1. (author)

[en] Malignant fibrous histiocytoma (MFH) is the most common soft tissue malignancy in adults. The Ga-67 citrate scan findings of an extremity-located MFH, the most common location of this neoplasm, have never been published in English language journals to the best of the authors' knowledge. Ga-67 citrate and Tc-99m MDP scans of the thigh mass accurately depicted the tumor's local extent, including the presence of central ischemic necrosis within the tumor, and the absence of adjacent osseous involvement and distant metastases, as correlated with computed tomography, angiography, and pathologic examinations

[en] The radiation response of 15 mammalian cell lines comprising 11 human tumour, two human fibroblast and two murine lymphoma cell lines, has been analysed using the linear-quadratic equation. The most striking result of this analysis was found in considering the α/β ratios. No relationship was observed between α_ac and β_ac resulting in values of α_ac/β_ac ranging from 1 to 175. In contrast a positive correlation was observed between α_ldr and β_RR in the 11 tumour cell lines, giving an α/β ratio of 9.4 ± 1.8 Gy. This observation of the relative constancy of the ratio for human tumour cells leads to an hypothesis about the role of initial damage as a determinant of radiosensitivity. (author)