Dayan shan biography of martin

Abstract

Iodine is a micronutrient needed for the production of thyroid hormones, which regulate metabolism, growth, and development. Iodine deficiency or excess may alter the thyroid hormone synthesis. The potential effects on infant development depend on the degree, timing, and duration of exposure. The iodine requirement is particularly high during infancy because of elevated thyroid hormone turnover. Breastfed infants rely on iodine provided by human milk, but the iodine concentration in breast milk is determined by the maternal iodine intake. Diets in many countries cannot provide sufficient iodine, and deficiency is prevented by iodine fortification of salt. However, the coverage of iodized salt varies between countries. Epidemiological data suggest large differences in the iodine intake in lactating women, infants, and toddlers worldwide, ranging from deficient to excessive intake. In this review, we provide an overview of the current knowledge and recent advances in the understanding of iodine nutrition and its association with thyroid function in lactating women, infants, and toddlers. We discuss risk factors for iodine malnutrition and the impact of targeted intervention strategies on these vulnerable population groups. We highlight the importance of appropriate definitions of optimal iodine nutrition and the need for more data assessing the risk of mild iodine deficiency for thyroid disorders during the first 2 years in life.

Keywords: iodine, deficiency, excess, lactation, infan

Graphical Abstract

ESSENTIAL POINTS.

• Iodine nutrition is a key determinant of thyroid function: Both iodine deficiency and excess may impair thyroid hormone production and thereby affect metabolism, growth, and development.

• The physiological iodine requirement is high in lactating women, infants, and toddlers, but current dietary intake recommendatio

For most of its history, China was organized into various dynastic states under the rule of hereditary monarchs. Beginning with the establishment of dynastic rule by Yu the Greatc. 2070 BC, and ending with the abdication of the Xuantong Emperor in AD 1912, Chinese historiography came to organize itself around the succession of monarchical dynasties. Besides those established by the dominant Han ethnic group or its spiritual Huaxia predecessors, dynasties throughout Chinese history were also founded by non-Han peoples.

Dividing Chinese history into dynastic epochs is a convenient and conventional method of periodization. Accordingly, a dynasty may be used to delimit the era during which a family reigned, as well as to describe events, trends, personalities, artistic compositions, and artifacts of that period. For example, porcelain made during the Ming dynasty may be referred to as "Ming porcelain".

The longest-reigning orthodox dynasty of China was the Zhou dynasty, ruling for a total length of about 790 years, albeit it is divided into the Western Zhou and the Eastern Zhou in Chinese historiography. The largest orthodox Chinese dynasty in terms of territorial size was either the Yuan dynasty or the Qing dynasty, depending on the historical source.

The term "Tiāncháo" (天朝; "Celestial Dynasty" or "Heavenly Dynasty") was frequently employed as a self-reference by Chinese dynasties. As a form of respect and subordination, Chinese tributary states referred to these dynasties as "Tiāncháo Shàngguó" (天朝上國; "Celestial Dynasty of the Exalted State") or "Tiāncháo Dàguó" (天朝大國; "Celestial Dynasty of the Great State").

Terminology

The Chinese character 朝 (cháo) originally meant "morning" or "today". Subsequently,

Abstract

Iron is the most abundant transition metal within the brain, and is vital for a number of cellular processes including neurotransmitter synthesis, myelination of neurons, and mitochondrial function. Redox cycling between ferrous and ferric iron is utilized in biology for various electron transfer reactions essential to life, yet this same chemistry mediates deleterious reactions with oxygen that induce oxidative stress. Consequently, there is a precise and tightly controlled mechanism to regulate iron in the brain. When iron is dysregulated, both conditions of iron overload and iron deficiencies are harmful to the brain. This review focuses on how iron metabolism is maintained in the brain, and how an alteration to iron and iron metabolism adversely affects neurological function.

Keywords: iron regulation, Alzheimer’s disease, Parkinson’s disease, iron deficiency, iron chelation

INTRODUCTION

Iron is a fundamental requirement for most known life forms, and is likely to have played an integral role in the earliest development of life on this planet (Russell et al., 1993). Organisms have evolved to harness the unique chemistry of this highly abundant metal, which make it integral to a vast array of chemical reactions supporting cell division, oxygen transport and mitochondrial function. The iron redox couple mediates the transfer of single electrons through the reversible oxidation/reduction reactions of Fe and Fe. Iron is a d-block transition metal, and the unoccupied d-orbitals allow ionic iron (II), iron (III), and iron (IV) species to form ligands with both small and large biomolecules via oxygen, nitrogen, and sulfur atoms. The biological redox potential and electronic spin state, and thereby reactivity of iron, is determined by the nature of the ligand to which the species is bound. This configuration, along with the oxidation state of the iron itself, dictates whether an iron-based biomolecule is responsible for reactions involv