Tạp chí khoa học số 2004-07-30

THIS WEEK IN edited by Stella Hurtley and Phil Szuromi CREDITS: (TOP TO BOTTOM) YAMADA ET AL.; BARTELS ET AL Strained and Stretched Nanoparticles genes coding for enzymes in the jasmonate signaling pathway, The electronic and optical properties of a material can change which is known to be involved in induced plant defense When on going from bulk materials to the nanoscale Gilbert et al planted into native habitats, the transformed plants were more (p 651, published online July 2004) show how confinement vulnerable not only to their specialist herbivores but also to effects can affect the bonding and packing of atoms They use a other herbivore species number of techniques to measure the lattice structure and internal strains in 3-nanometer particles of zinc sulfide A comPop Goes the Mitochondrion plex pattern of internal strains results as the particles attempt to lower the surface energy These strains cause a reduction in In cells undergoing apoptosis or cell death, mitochondria, the the overall ordering and a stiffening of the lattice When metals powerhouses of the cell, often have a key role Not only is cellular metabolism shut down, but are deformed, the crystalline mitochondria release molecules grains can rotate and realign, into the cytoplasm that further much in the way that painted Controlling Interface Spin promote cell death Substantial shapes will stretch and warp controversy has surrounded the The magneto-electronic properties of heterojunction when a canvas is pulled in a mechanisms by which these structures formed between magnetic thin films and inspecific direction Shan et al processes occur Green and Kroesulating layers are attractive for potential device appli(p 654; see the Perspective by mer (p 626) review the role of cations However, the beMa) find that in nanocrystalline mitochondria in cell death Perhavior of such structures nickel, this type of deformation meabilization of the mitochondria has been unpredictable, dominates, unlike the situation can be the point-of-no-return and techniques are needwith coarser grained metals, that seals the fate of a cell, and ed that can investigate where the production of grain numerous strategies are envithe influence of interface boundary defects and dislocasioned to alter these processes region Using magnetizations accommodates most of therapeutically to benefit patients tion-induced second-harthe deformation energy These suffering from a range of illnesses monic generation, Yamaresults confirm many observafrom cancer and heart failure to da et al (p 646) show tions obtained from computer neurodegeneration that they can probe and simulations and should help characterize the magneguide the design of optimum tization of buried intermetals and alloys Herbivores Drive faces formed between Diversity manganite and insulating Lunar Meteorite Habitat specialization and betathin films Moreover, by Phones Home diversity—the change in species grading the doping level composition between sites—may of the interface region, they show how the properties A lunar meteorite found in the explain a large part of the overall can be altered in a controlled manner Sultanate of Oman (Sayh al diversity within tropical forests Uhaymir 169) consists of four However, why beta-diversity different impact breccias and is enriched in potassium, rare earth elements, and phosphorus should be higher in the tropics remains unclear To test the Gnos et al (p 657; see the Perspective by Korotev) used iso- hypothesis that herbivores promote habitat specialization, Fine topic systematics to date the four impact events that occurred et al (p 663; see the Perspective by Marquis) performed recipwhile the rock was at or near the surface of the Moon The im- rocal transplant experiments of specialist tree seedlings bepact event dates of 3900 million years ago (Ma), 2800 Ma, 200 tween soil types in the Peruvian Amazon, and also manipulated Ma, and