THIS WEEK IN Science.

The article introduces several research papers in the issue. A paper by Srivastava et al. reports on the techniques used to make helical nanoparticles, including oxidation of cadmium-tellurium, application of visible light, and doping with cadmium sulfide nanoparticles. Research by Ito et al. on thalidomide exposure indicates that its teratogenetic effects are exerted through binding with the protein cereblon. Iess et al. report on evaluations of the mass and geology of Titan, a moon of Saturn, based on gravity data collected by the Cassini space vehicle.