5,175 research outputs found
Gallium-transferrin as a macromolecular tracer of vascular permeability.
No full textLabeling of plasma transferrin with gallium was investigated to determine whether the gallium-transferrin complex could be effectively used as a macromolecular tracer in studies of capillary permeability using Positron Emission Tomography (PET). Three gallium-plasma preparations were tested and 2 h biodistribution studies were performed in rats. The three preparations gave similar blood clearance and tissue distribution data, but the methods used for evaluating gallium-transferrin binding were found to be suboptimal. Gallium clearance from blood was biexpoential with both components faster than that of 125I-albumin. Gallium distribution spaces in all tissues including intracerebral Walker-256 tumors were larger than those of albumin. These results indicate a relative instability of the gallium-transferrin complex in vivo, which appears to preclude its use as an acceptable radiolabeled protein for vascular permeability studies using PET
Yeast metabolism in fresh and frozen dough : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Food Technology at Massey University, Palmerston North, New Zealand
No full textAuthor also known as SM LovedayFresh bakery products have a very short shelf life, which limits the extent to which manufacturing can be centralised. Frozen doughs are relatively stable and can be manufactured in large volumes, distributed and baked on-demand at the point of sale or consumption. With appropriate formulation and processing a shelf life of several months can be achieved.Shelf life is limited by a decline in proofing rate after thawing, which is attributed to a) the dough losing its ability to retain gas and b) insufficient gas production, i.e. yeast activity. The loss of shelf life is accelerated by delays between mixing and freezing, which allow yeast cells the chance to ferment carbohydrates.This work examined the reasons for insufficient gas production after thawing frozen dough and the effect of pre-freezing fermentation on shelf life. Literature data on yeast metabolite dynamics in fermenting dough were incomplete. In particular there were few data on the accumulation of ethanol, a major fermentation end product which can be injurious to yeast.Doughs were prepared in a domestic breadmaker using compressed yeast from a local manufacturer and analysed for glucose, fructose, sucrose, maltose and ethanol. Gas production after thawing declined within 48 hours of frozen storage. This was accelerated by 30 or 90 minutes of fermentation at 30;C prior to freezing.Sucrose was rapidly hydrolysed and yeast consumed glucose in preference to fructose. Maltose was not consumed while other sugars remained. Ethanol, accumulated from consumption of glucose and fructose, was produced in approximately equal amounts to CO2, indicating that yeast cells metabolised reductively.Glucose uptake in fermenting dough followed simple hyperbolic kinetics and fructose uptake was competitively inhibited by glucose. Mathematical modelling indicated that diffusion of sugars and ethanol in dough occurred quickly enough to eliminate solute gradients brought about by yeast metabolism
Segmentation of lung lesion volume by adaptive positron emission tomography image thresholding.
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Thallium-201 scintigraphy for the evaluation of tumor response to preoperative chemotherapy in patients with osteosarcoma.
No full textA new parameter for measuring metastatic bone involvement by prostate cancer: the Bone Scan Index.
No full textDiagnosis of coronary artery disease by radionuclide angiography: effect of combining indices of left ventricular function
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