Seed germination and subsequent seedling growth define crucial steps for entry into the plant life cycle. For those events to take place properly, seed developmental genes need to be silenced whereas vegetative growth genes are activated. Chromatin structure is generally known to play crucial roles in gene transcription control. However, the transition between active and repressive chromatin st...

To the Editor: Paredes et al1,2 showed, in a manuscript published recently in Science, that human postnatal neurogenesis occurs in noncanonical niches in the frontal lobe and that immature interneurons migrate long distances even in the postmortem brain. These immature interneurons are likely to be postmitotic neurons born principally in the medial ganglionic eminence (MGE; Figure A).1,3,4 The ...

BY W. T. MASON, S. R. RAWLINGS, P. COBBETT, S. K. SIKDAR, R. ZOREC , S. N. AKERMAN, C. D. BENHAM, M. J. BERRIDGE, T. CHEEK AND R. B. MORETON 1 Department of Neuroendocrinology, AFRC Institute of Animal Physiology and Genetics Research, Babraham, Cambridge CB2 4AT, UK, Department of Pharmacology, Smith Kline & French Research Ltd, The Frythe, Welwyn, Hertfordshire AL6 9AR, UK, ^AFRC Unit of Inse...

Abstract:In this study, an effort has been made to determine the influence of rotational speed of tool on themicrostructure and hardness values of friction stir welded 2024-T851 aluminum alloy. The microstructure of stir zonein the joints has been investigated. It was found that the particles such as Al6(CuFeMn) particles are broken up duringfriction stir welding, and the degree of break up of ...

C and metallic bonding in solids profoundly impacts their properties, which have been widely exploited by humankind since ancient times. More exotic types of chemical bonding in solids are also known, for example, mixed ioniccovalent bonding characteristic of certain ceramics and perovskites. The basic classification of materials according to the type of chemical bonding in them goes together w...

In this study, the composition templating theory for heterogeneous nucleation was applied to achieve TiB2 particles with Mn segregation on surface, which supplied initial nucleation. The interfacial of added alloy element and other common impurities, such as Fe Si, investigated scanning transmission electron microscopy (STEM). modified in Al-2.0Mn-1.0Fe alloys test its effects grain refinement ...