@article{1747, abstract = {We report on recent advances in the understanding of surface processes occurring during growth and post-growth annealing of strained islands which may find application as self-assembled quantum dots. We investigate the model system SiGe/Si(0 0 1) by a new approach based on "reading the footprints" which islands leave on the substrate during their growth and evolution. Such footprints consist of trenches carved in the Si substrate. We distinguish between surface footprints and footprints buried below the islands. The former allow us to discriminate islands which are in the process of growing from those which are shrinking. Islands with steep morphologies grow at the expense of smaller and shallower islands, consistent with the kinetics of anomalous coarsening. While shrinking, islands change their shape according to thermodynamic predictions. Buried footprints are investigated by removing the SiGe epilayer by means of selective wet chemical etching. Their reading shows that: (i) during post-growth annealing islands move laterally because of surface-mediated Si-Ge intermixing; (ii) a tree-ring structure of trenches is created by dislocated islands during their "cyclic" growth. This allows us to distinguish coherent from dislocated islands and to establish whether the latter are the result of island coalescence.}, author = {Rastelli, Armando and Stoffel, Mathieu and Georgios Katsaros and Tersoff, Jerry and Denker, Ulrich and Merdzhanova, Tsvetelina and Kar, Gouranga S and Costantini, Giovanni and Kern, Klaus and Von Känel, Hans and Schmidt, Oliver G}, journal = {Microelectronics Journal}, number = {12}, pages = {1471 -- 1476}, publisher = {Elsevier}, title = {{Reading the footprints of strained islands}}, doi = {10.1016/j.mejo.2006.05.029}, volume = {37}, year = {2006}, } @article{1746, abstract = {A microscopic picture for the GaAs overgrowth of self-organized InAs/GaAs(001) quantum dots is developed. Scanning tunneling microscopy measurements reveal two capping regimes: the first being characterized by a dot shrinking and a backward pyramid-to-dome shape transition. This regime is governed by fast dynamics resulting in island morphologies close to thermodynamic equilibrium. The second regime is marked by a true overgrowth and is controlled by kinetically limited surface diffusion processes. A simple model is developed to describe the observed structural changes which are rationalized in terms of energetic minimization driven by lattice mismatch and alloying.}, author = {Costantini, Giovanni and Rastelli, Armando and Manzano, Carlos and Acosta-Diaz, P and Songmuang, Rudeeson and Georgios Katsaros and Schmidt, Oliver G and Kern, Klaus}, journal = {Physical Review Letters}, number = {22}, publisher = {American Physical Society}, title = {{Interplay between thermodynamics and kinetics in the capping of InAs/GaAs (001) quantum dots}}, doi = {10.1103/PhysRevLett.96.226106}, volume = {96}, year = {2006}, } @article{1748, abstract = {The authors apply selective wet chemical etching and atomic force microscopy to reveal the three-dimensional shape of SiGeSi (001) islands after capping with Si. Although the "self-assembled quantum dots" remain practically unaffected by capping in the temperature range of 300-450 °C, significant morphological changes take place on the Si surface. At 450 °C, the morphology of the capping layer (Si matrix) evolves toward an intriguing semifacetted structure, which we call a "ziggurat," giving the misleading impression of a stepped SiGe island shape.}, author = {Georgios Katsaros and Rastelli, Armando and Stoffel, Mathieu and Costantini, Giovanni and Schmidt, Oliver G and Kern, Klaus and Tersoff, Jerry and Müller, Elisabeth and Von Känel, Hans}, journal = {Applied Physics Letters}, number = {25}, publisher = {American Institute of Physics}, title = {{Evolution of buried semiconductor nanostructures and origin of stepped surface mounds during capping}}, doi = {10.1063/1.2405876}, volume = {89}, year = {2006}, } @article{1796, abstract = {Drugs that block the entry of human immunodeficiency virus type 1 (HIV-1) into host cells abrogate the establishment of a productive infection and should ideally diminish the chances of HIV-1 developing resistance. This review will give an overview of the mechanism by which the envelope glycoprotein mediates HIV-1 entry and will summarize current drug developments.}, author = {Sandra Siegert and Schnierle, Peter and Schnierle, Barbara S}, journal = {Mini-Reviews in Medicinal Chemistry}, number = {5}, pages = {557 -- 562}, publisher = {Bentham Science Publishers}, title = {{Novel anti-viral therapy: Drugs that block HIV entry at different target sites}}, doi = {10.2174/138955706776876267}, volume = {6}, year = {2006}, } @article{1961, abstract = {Respiratory complex I plays a central role in cellular energy production in bacteria and mitochondria. Its dysfunction is implicated in many human neurodegenerative diseases, as well as in aging. The crystal structure of the hydrophilic domain (peripheral arm) of complex I from Thermus thermophilus has been solved at 3.3 angstrom resolution. This subcomplex consists of eight subunits and contains all the redox centers of the enzyme, including nine iron-sulfur clusters. The primary electron acceptor, flavin-mononucleotide, is within electron transfer distance of cluster N3, leading to the main redox pathway, and of the distal cluster Nia, a possible antioxidant. The structure reveals new aspects of the mechanism and evolution of the enzyme. The terminal cluster N2 is coordinated, uniquely, by two consecutive cysteines. The novel subunit Nqo15 has a similar fold to the mitochondrial iron chaperone frataxin, and it may be involved in iron-sulfur cluster regeneration in the complex. }, author = {Leonid Sazanov and Hinchliffe, Philip }, journal = {Science}, number = {5766}, pages = {1430 -- 1436}, publisher = {American Association for the Advancement of Science}, title = {{Structure of the hydrophilic domain of respiratory complex I from Thermus thermophilus}}, doi = {10.1126/science.1123809}, volume = {311}, year = {2006}, }