Contents: (Small 20/2010)

Nanoporous materialsThe cover image shows a nanofi lter for atmospheric gas separation produced by porous graphene supported on a classical porous material such as Al 2 O 3 .The functionality of this membrane is analyzed with fi rst-principle calculations showing that it is superior to traditional fi lters using polymers or silica.Due to the extremely high selectivity in favor of hydrogen and helium among other atmospheric gases, the present membrane has high potential for further technological applications such as gas sensors or fuel cells.For more information, please read the Full Paper "Porous Graphene as an Atmospheric Nanofi lter" by S. Blankenburg and co-workers, beginning on page 2266. Self-assemblyThe cover picture shows hierarchically ordered structures, which are achieved by combining two self-assembly processes at different length scales, namely, top-down controlled evaporative self-assembly and bottom-up spontaneous self-assembly of nanomaterials, i.e., comb block copolymers (CBCPs).Highly ordered, microscopic concentric CBCP rectangles are formed in a gradient arrangement via evaporative selfassembly as a result of controlled pinning and depinning of a three-phase contact line of evaporating CBCP toluene solution confi ned in a wedge-on-fl at geometry.Subsequent solvent vapor annealing promotes spontaneous microphase separation of the CBCP, thereby leading to the formation of vertically aligned nanocylinders.For more information, please read the Communication "Hierarchically Ordered Structures Enabled by Controlled Evaporative Self-Assembly" by Z. Lin and co-workers, beginning on page 2250. Quantum dotsThe frontispiece image shows tumor (green) at the microscopic level in living mice.Within the tumor, blood vessels in red are easily visible.When targeted, nanoparticles (quantum dots, shown in white) bind as aggregates in a similar way to three different types of tumor (one example is shown at bottom left).However, when controls are used, very little binding takes place as shown in the other images.Data indicate that vascular targeting may be a robust and reliable method to promote nanoparticle accumulation in a tumor, as opposed to extravasation, which is shown to be highly heterogeneous.For more information, please read the Full Paper "Dynamic Visualization of RGD-Quantum Dot Binding to Tumor Neovasculature and Extravasation in Multiple Living Mouse Models Using Intravital Microscopy" by S. S. Gambhir and co-workers, beginning on page 2222.