A review of recent developments in the speciation and location of arsenic and selenium in rice grain

Rice is a staple food yet is a significant dietary source of inorganic arsenic, a class 1, nonthreshold carcinogen. Establishing the location and speciation of arsenic within the edible rice grain is essential for understanding the risk and for developing effective strategies to reduce grain arsenic concentrations. Conversely, selenium is an essential micronutrient and up to 1 billion people worldwide are selenium-deficient. Several studies have suggested that selenium supplementation can reduce the risk of some cancers, generating substantial interest in biofortifying rice. Knowledge of selenium location and speciation is important, because the anti-cancer effects of selenium depend on its speciation. Germanic acid is an arsenite/silicic acid analogue, and location of germanium may help elucidate the mechanisms of arsenite transport into grain. This review summarises recent discoveries in the location and speciation of arsenic, germanium, and selenium in rice grain using state-of-the-art mass spectrometry and synchrotron techniques, and illustrates both the importance of high-sensitivity and high-resolution techniques and the advantages of combining techniques in an integrated quantitative and spatial approach.

Phloem transport of arsenic species from flag leaf to grain during grain filling

Strategies to reduce arsenic (As) in rice grain, below concentrations that represent a serious human health concern, require that the mechanisms of As accumulation within grain be established. Therefore, retranslocation of As species from flag leaves into filling rice grain was investigated.

Arsenic species were delivered through cut flag leaves during grain fill. Spatial unloading within grains was investigated using synchrotron X-ray fluorescence (SXRF) microtomography. Additionally, the effect of germanic acid (a silicic acid analog) on grain As accumulation in arsenite-treated panicles was examined.

Dimethylarsinic acid (DMA) and monomethylarsonic acid (MMA) were extremely efficiently retranslocated from flag leaves to rice grain; arsenate was poorly retranslocated, and was rapidly reduced to arsenite within flag leaves; arsenite displayed no retranslocation. Within grains, DMA rapidly dispersed while MMA and inorganic As remained close to the entry point. Germanic acid addition did not affect grain As in arsenite-treated panicles. Three-dimensional SXRF microtomography gave further information on arsenite localization in the ovular vascular trace (OVT) of rice grains.

These results demonstrate that inorganic As is poorly remobilized, while organic species are readily remobilized, from leaves to grain. Stem translocation of inorganic As may not rely solely on silicic acid transporters.

Beowulf Hondbona: the Literary Context for Emending Line 1520b

In this article I consider the debate over whether line 1520b ought to be read as the emended “hond sweng” or the scribal “hord swenge.” It is a small point philologically but it raises interesting cultural and literary questions about the attitude of the Beowulf poet to arms and armour, to aggressive and defensive war gear, and to swords in particular. It has widely been assumed that swords are important in Beowulf and yet, the question of what their significance might be has received very little attention. Throughout the poem the hero is plagued by breaking, melting, and failing swords. He borrows, finds, and is given swords but unlike other English and Germanic heroes he is never identified with a single, great sword. I suggest that this is because, ultimately, Beowulf is conceived as a hondbana, a designation which has implications for what kind of a hero he proves to be.

Germany and the New Global History of Secularism: Questioning the Postcolonial Genealogy

Secularism has emerged as a central category of twenty-first century political thought that in many ways has replaced the theory of secularization. According to postcolonial scholars, neither the theory nor the practice of secularization was politically neutral. They define secularism as the set of discourses, policies, and constitutional arrangements whereby modern states and liberal elites have sought to unify nations and divide colonial populations. This definition is quite different from the original meaning of secularism, as an immanent scientific worldview linked to anticlericalism. Anthropologist Talal Asad has connected nineteenth-century worldview secularism to twenty-first century political secularism through a genealogical account that stresses continuities of liberal hegemony. This essay challenges this account. It argues that liberal elites did not merely subsume worldview secularism in their drive for state secularization. Using the tools of conceptual history, the essay shows that one reason that “secularization” only achieved its contemporary meaning in Germany after 1945 was that radical freethinkers and other anticlerical secularists had previously resisted liberal hegemony. The essay concludes by offering an agenda for research into the discontinuous history of these two types of secularism.