Abstract: Provided herein are systems, methods and compositions for rendering cells or the expression of an effector protein sensitive to a predetermined condition. In one aspect, cells can be rendered dependent upon the presence of an environmental agent, e.g., an exogenous agent, without which the cell will default to expression of a death protein and be killed. In another aspect, cells can be rendered sensitive to the presence of a set of predetermined conditions such that cells will only grow when two or more necessary exogenous agents are supplied, and without either of which, the cells are killed. In this aspect, hybrid transcription factors provide a vast array of possible predetermined conditions.

Abstract: Provided herein are systems, methods and compositions for rendering cells or the expression of an effector protein sensitive to a predetermined condition. In one aspect, cells can be rendered dependent upon the presence of an environmental agent, e.g., an exogenous agent, without which the cell will default to expression of a death protein and be killed. In another aspect, cells can be rendered sensitive to the presence of a set of predetermined conditions such that cells will only grow when two or more necessary exogenous agents are supplied, and without either of which, the cells are killed. In this aspect, hybrid transcription factors provide a vast array of possible predetermined conditions.

Abstract: This invention provides reductase proteins that comprise NH2Y unnatural amino acid residues, systems of orthogonal elements for incorporating NH2Y into reductases and methods of using NH2Y amino acid residues in reductases as molecular probes for probing reductases function, structure and activity.

Abstract: A method and apparatus for rotatably interconnecting computer storage disks to a stationary base is provided. The apparatus provides a hybrid bearing assembly having an oil-filled thrust bearing and an air-filled radial bearing. In particular, the apparatus provides a hybrid bearing having an oil-filled thrust bearing that is highly resistant to leakage. In addition, the apparatus provides a hybrid bearing having a radial air bearing with a very large diameter to provide great stiffness in a radial direction using common manufacturing tolerances. The method of the present invention includes rotatably interconnecting a hub for suspending computer storage media to a base or enclosure using an oil-filled thrust bearing and an air-filled radial bearing. The method further includes balancing the pressures in both directions along the axis of the thrust bearing to prevent leakage of the oil from the bearing. The method also includes providing an air bearing having a very large diameter.