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Nm Resolution (nm + resolution)
Selected AbstractsScanning Kelvin Probe Microscopy on Bulk Heterojunction Polymer BlendsADVANCED FUNCTIONAL MATERIALS, Issue 9 2009Klára Maturová Abstract Here, correlated AFM and scanning Kelvin probe microscopy measurements with sub-100,nm resolution on the phase-separated active layer of polymer-fullerene (MDMO-PPV:PCBM) bulk heterojunction solar cells in the dark and under illumination are described. Using numerical modeling a fully quantitative explanation for the contrast and shifts of the surface potential in dark and light is provided. Under illumination an excess of photogenerated electrons is present in both the donor and acceptor phases. From the time evolution of the surface potential after switching off the light the contributions of free and trapped electrons can be identified. Based on these measurements the relative 3D energy level shifts of the sample are calculated. Moreover, by comparing devices with fine and coarse phase separation, it is found that the inferior performance of the latter devices is, at least partially, due to poor electron transport. [source] Patterning Colloidal Metal Nanoparticles for Controlled Growth of Carbon Nanotubes,ADVANCED MATERIALS, Issue 24 2008Bing Li Single-walled carbon-nanotube (SWCNT) arrays are generated on catalyst patterns with controlled location, orientation, and spacing using a straightforward approach. Dip-pen nanolithography is used to fabricate catalyst patterns with sub-70 nm resolution, and SWCNTs are successfully grown on these patterns through chemical vapor deposition. The growth direction of the SWCNTs on quartz is controlled, and along the [100] crystallographic direction. [source] Discovery of the Porosome: revealing the molecular mechanism of secretion and membrane fusion in cellsJOURNAL OF CELLULAR AND MOLECULAR MEDICINE, Issue 1 2004B. P. Jena Abstract Secretion and membrane fusion are fundamental cellular processes involved in the physiology of health and disease. Studies within the past decade reveal the molecular mechanism of secretion and membrane fusion in cells. Studies reveal that membrane-bound secretory vesicles dock and fuse at porosomes, which are specialized plasma membrane structures. Swelling of secretory vesicles result in a build-up of intravesicular pressure, which allows expulsion of vesicular contents. The discovery of the porosome, its isolation, its structure and dynamics at nm resolution and in real time, its biochemical composition and functional reconstitution, are discussed. The molecular mechanism of secretory vesicle fusion at the base of porosomes, and vesicle swelling, have been resolved. With these findings a new understanding of cell secretion has emerged and confirmed by a number of laboratories. [source] Structures of Cytochrome b5 Mutated at the Charged Surface-Residues and Their Interactions with Cytochrome c,CHINESE JOURNAL OF CHEMISTRY, Issue 11 2002Jlan Wu Abstract Glu44, Glu48, Ghi56 and Asp60 are the negatively charged residues located at the molecular surface of cytochrome b5. Two mutants of cytochrome b5 were prepared, in which two or all of these four residues were mutated to alanines. The mutations give rise to slightly positive shifts of the redox potentials of cytochrome b5 and obvious decrease of the cytochrome b5 -cytochrome c binding constants and electron transfer rates. The crystal structures of the two mutants were determined at 0.18 nm resolution, showing no alteration in overall structures and exhibiting slight changes in the local conformations around the mutation sites as compared with the wild-type protein. Based on the crystal structure of the quadruple-site mutant, a model for the binding of this mutant with cytochrome c is proposed, which involves the salt bridges from Glu37, Glu38 and heme propionate of cytochrome b5 to three lysines of cytochrome c and can well account for the properties and behaviors of this mutant. [source] | ||||||||||