Biomarkers of Nutrition for Development (BOND)—Iron Review

This is the fifth in the series of reviews developed as part of the Biomarkers of Nutrition for Development (BOND) program. The BOND Iron Expert Panel (I-EP) reviewed the extant knowledge regarding iron biology, public health implications, and the relative usefulness of currently available biomarkers of iron status from deficiency to overload. Approaches to assessing intake, including bioavailability, are also covered. The report also covers technical and laboratory considerations for the use of available biomarkers of iron status, and concludes with a description of research priorities along with a brief discussion of new biomarkers with potential for use across the spectrum of activities related to the study of iron in human health. The I-EP concluded that current iron biomarkers are reliable for accurately assessing many aspects of iron nutrition. However, a clear distinction is made between the relative strengths of biomarkers to assess hematological consequences of iron deficiency versus other putative functional outcomes, particularly the relationship between maternal and fetal iron status during pregnancy, birth outcomes, and infant cognitive, motor and emotional development. The I-EP also highlighted the importance of considering the confounding effects of inflammation and infection on the interpretation of iron biomarker results, as well as the impact of life stage. Finally, alternative approaches to the evaluation of the risk for nutritional iron overload at the population level are presented, because the currently designated upper limits for the biomarker generally employed (serum ferritin) may not differentiate between true iron overload and the effects of subclinical inflammation

A circuit design to generate and maintain a constant magnetic flux

A circuit designed to generate and maintain a constant magnetic flux is presented by using a sample-data control system, instead of a continuous control system. A Hall generator is used as the magnetic sensing element, and is operated with a pulse bias to allow a large output. The output of the Hall generator is compared to a reference signal, and strobed to obtain an output pulse with low distortion. These techniques are discussed in detail A block diagram of the system with some important requirements are discussed as well as the method of the circuit design. The method of testing the system in order to determine the stability of the system is described. The complete system shows that it is possible to obtain good results and may be applied to a larger system if required