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Query: UNIPROT:P02794 (ferritin)
 17,525 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A comparison is made of the deblurring by digital and optical processing of a single conventional bright field electron image of ferritin particles distributed on a carbon supporting film. The deblurring functions include the effects of the partial temporal and partial spatial coherence of the electron beam, the phase contrast transfer function of the objective lens and Weiner signal to noise optimisation. Practical aspects of the similar results achieved by the two methods are discussed. The relative advantages and disadvantages of the batch and interactive computer modes for picture processing are considered in an Appendix.
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PMID:Optical and digital image processing in high-resolution electron microscopy. 88 34

Gastrointestinal side effects were selected as the critical adverse effects on which to base the UL for iron. Although gastrointestinal distress is not a serious side effect when compared with the possible risk for vascular disease and cancer, the other side effects considered (impaired zinc absorption, increased risk for vascular disease and cancer, and systemic iron overload) did not permit the determination of a UL. Gastrointestinal distress is primarily observed in individuals who have consumed high levels of supplemental iron on an empty stomach. Large doses of iron supplements may inhibit zinc absorption when both are consumed in the fasting state, but zinc absorption is not impaired when supplementary iron is taken with meals. The relationship between iron intake and both vascular disease and cancer is unclear at the present time. With the possible exception of individuals living in Southern Africa who suffer from sub-Saharan iron overload, iron overload has not been shown to result solely from a high dietary iron intake. Moreover, no differences were found in the serum ferritin concentrations between individuals who fell in the lower and upper quartiles for total dietary iron intake in the Third National Health and Nutrition Examination Survey (NHANES 111) (Appendix Table H-5). Heterozygous carriers of the C282Y mutation most commonly associated with hereditary hemochromatosis could be at increased risk for accumulating harmful amounts of iron, but there are no direct observations to confirm this suspicion. Homozygotes and individuals with other iron-loading disorders may not be protected by the UL and are addressed under "Special Considerations".
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PMID:Iron: tolerable upper intake levels. 1245 26

The rational development of new generations of MRI contrast agents (CAs) requires a scheme for predicting contrast enhancement. Previous contrast predictions have been based largely on empirical results in specific systems. Here we present a general theoretical model for evaluating the minimum concentration of T2 CA required for satisfactory image contrast. This analytic contrast model is applicable to a wide range of T2-type agents and delivery scenarios, and requires only a few readily evaluated parameters. We demonstrated the model by predicting contrast produced by superparamagnetic ferumoxide and the iron storage protein, ferritin. We then experimentally verified the predictions using suspensions of Feridex(R) and ferritin in phantoms. The model was also used to compare the contrast efficacy of the metal ions in two clinically approved T1- and T2-type CAs. In the Appendix we present a numerical formalism that is useful for relating image contrast and agent concentration when gradient-echo (GRE) T2*-weighted (T2*W) pulse sequences are used.
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PMID:Theoretical MRI contrast model for exogenous T2 agents. 1726 Mar 82