Tube-shaped nanostructures (nanotubes) have a number of attributes that make them potentially useful for biomedical applications such as drug delivery/detoxification and enzyme immobilization. Template synthesis provides a route for preparing monodisperse nanotubes of nearly any size and composed of nearly any material. We show here that template-synthesized silica nanotubes can be biochemically functionalized such that they act as biocatalysts and highly selective nano-phase extraction agents for bioseparations. For example, nanotubes containing an enantioselective antibody selectively extract the enantiomer of a drug molecule that binds to the antibody, relative to the enantiomer that has no specific interaction with the antibody. Nanotubes containing the enzyme glucose oxidase function as nanophase bioreactors to catalyze the oxidation of glucose.

Synthetic bio-nanotube membranes were developed and used to separate two enantiomers of a chiral drug. These membranes are based on alumina films that have cylindrical pores with monodisperse nanoscopic diameters (for example, 20 nanometers). Silica nanotubes were chemically synthesized within the pores of these films, and an antibody that selectively binds one of the enantiomers of the drug was attached to the inner walls of the silica nanotubes. These membranes selectively transport the enantiomer that specifically binds to the antibody, relative to the enantiomer that has lower affinity for the antibody. The solvent dimethyl sulfoxide was used to tune the antibody binding affinity. The enantiomeric selectivity coefficient increases as the inside diameter of the silica nanotubes decreases.

This article assesses the impact of globalization on welfare state effort in the OECD countries. Globalization is defined in terms of total trade, imports from low wage economies, foreign direct investment, and financial market integration. Welfare effort is analyzed in terms both of public spending (and separately on social service provision and income transfer programs) and taxation (effective rates of capital taxation and the ratio of capital to labor and consumption taxes). Year-to-year increases in total trade and international financial openness in the past three decades have been associated with less government spending. In contrast, integration into global markets has not been associated either with reductions in capital tax rates, or with shifts in the burden of taxation from capital to consumption and labor income. Moreover, countries with greater inflows and outflows of foreign direct investment tend to tax capital more heavily.