Comments on enzyme assays

Comments on enzyme assay

The development and application of the use of encased voids within the body of glass artefacts as a means of drawing and expression

This practice -led thesis is based on a study of the use of encased voids or bubbles in glass. The study is grounded in practice and draws out through antecedents in philosophy, psychology and epistemology, a methodology called Reflective Risk. It shows that through a rigorous analysis of practice, using video and personal reflection that new insights emerge. The study is framed by craft practice (the word craft here used as a collection of 'genre' of which glass is part). The thesis uses experiential learning as a tool and a means of understanding the practice of creating and controlling encased voids in glass in the context of contemporary applied arts practice. The framework, Reflective Risk, is constructivist in approach. It is based on Experiential Learning Theory (ELT), but it also draws on epistemological theories of tacit knowledge. The thesis shows that through an understanding of technique and material qualities, process can be deconstructed to reveal new insights. The thesis documents how an understanding ELT and a range of self- regulatory antecedents can influence the cognitive process of craft practice through praxis. The results of this study, on the one hand, are directed to glass practitioners and on the other, to provide a theoretical approach appropriate for the reflective practitioner working in other media by adopting a parallel method of enquiry

Glyoxylate cycle mutants in Neurospora

Glyoxylate cycle mutants in Neurospor

Effect of Time-of-Flight and Regularized Reconstructions on Quantitative Measurements and Qualitative Assessments in Newly Diagnosed Prostate Cancer With 18F-Fluorocholine Dual Time Point PET/MRI.

Recent technical advances in positron emission tomography/magnetic resonance imaging (PET/MRI) technology allow much improved time-of-flight (TOF) and regularized iterative PET reconstruction regularized iterative reconstruction (RIR) algorithms. We evaluated the effect of TOF and RIR on standardized uptake values (maximum and peak SUV [SUVmax and SUVpeak]) and their metabolic tumor volume dependencies and visual image quality for 18F-fluorocholine PET/MRI in patients with newly diagnosed prostate cancer. Fourteen patients were administered with 3 MBq/kg of 18F-fluorocholine and scanned dynamically for 30 minutes. Positron emission tomography images were divided to early and late time points (1-6 minutes summed and 7-30 minutes summed). The values of the different SUVs were documented for dominant PET-avid lesions, and metabolic tumor volume was estimated using a 50% isocontour and SUV threshold of 2.5. Image quality was assessed via visual acuity scoring (VAS). We found that incorporation of TOF or RIR increased lesion SUVs. The lesion to background ratio was not improved by TOF reconstruction, while RIR improved the lesion to background ratio significantly ( P < .05). The values of the different VAS were all significantly higher ( P < .05) for RIR images over TOF, RIR over non-TOF, and TOF over non-TOF. In conclusion, our data indicate that TOF or RIR should be incorporated into current protocols when available

Imaging glutathione depletion in the rat brain using ascorbate-derived hyperpolarized MR and PET probes.

Oxidative stress is a critical feature of several common neurologic disorders. The brain is well adapted to neutralize oxidative injury by maintaining a high steady-state concentration of small-molecule intracellular antioxidants including glutathione in astrocytes and ascorbic acid in neurons. Ascorbate-derived imaging probes for hyperpolarized 13C magnetic resonance spectroscopy and positron emission tomography have been used to study redox changes (antioxidant depletion and reactive oxygen species accumulation) in vivo. In this study, we applied these imaging probes to the normal rat brain and a rat model of glutathione depletion. We first studied hyperpolarized [1-13C]dehydroascorbate in the normal rat brain, demonstrating its robust conversion to [1-13C]vitamin C, consistent with rapid transport of the oxidized form across the blood-brain barrier. We next showed that the kinetic rate of this conversion decreased by nearly 50% after glutathione depletion by diethyl maleate treatment. Finally, we showed that dehydroascorbate labeled for positron emission tomography, namely [1-11C]dehydroascorbate, showed no change in brain signal accumulation after diethyl maleate treatment. These results suggest that hyperpolarized [1-13C]dehydroascorbate may be used to non-invasively detect oxidative stress in common disorders of the brain