Abstract: Provided are methods and compositions for regulating gene expression in a cell. The invention provides recombinant adjustable-threshold switches which contain a first inducible promoter-regulatory gene operon and a second constitutive promoter-regulatory gene operon. A threshold amount of activating agent is required to switch the inducible promoter “on” and the constitutive promoter “off”. An adjustable-threshold switch is useful to reversibly switch the expression of a gene of interest between a stable “on” state and stable “off” state in response to an activating agent at or above a threshold concentration.

Abstract: Provided are methods and compositions for regulating gene expression in a cell. The invention provides recombinant multi-state genetic oscillators containing an adjustable-threshold genetic switch that is periodically activated by an oscillating amount of an activator agent. The activating agent is a gene product expressed from a promoter regulated by the adjustable-threshold switch and thus forms a feedback loop that causes periodic switching of the adjustable-threshold switch between an “on” state and an “off” state. Multi-state genetic oscillators are useful to express one or more genes of interest in a periodic manner without requiring a periodic application of an external activating agent.

Abstract: Provided are methods and compositions for regulating gene expression in a cell. The invention provides recombinant adjustable-threshold switches which contain a first inducible promoter-regulatory gene operon and a second constitutive promoter-regulatory gene operon. A threshold amount of activating agent is required to switch the inducible promoter “on” and the constitutive promoter “off”. An adjustable-threshold switch is useful to reversibly switch the expression of a gene of interest between a stable “on” state and stable “off” state in response to an activating agent at or above a threshold concentration.

Abstract: Provided are methods and compositions for regulating gene expression in a cell. The invention provides recombinant genetic toggle switches which contain a first constitutive promoter-regulatory gene operon and a second constitutive promoter-regulatory gene operon. Expression of the regulatory gene from the first operon inhibits expression from the promoter in the second operon, and expression of the regulatory gene from the second operon inhibits expression from the promoter in the first operon. By use of the toggle switch and various switching agents it is possible to reversibly switch the expression of a gene of interest between a stable “on” state and stable “off” state or vice versa via transient exposure to a switching agent.

Abstract: Provided are methods and compositions for regulating gene expression in a cell. The invention provides recombinant multi-state genetic oscillators containing an adjustable-threshold genetic switch that is periodically activated by an oscillating amount of an activator agent. The activating agent is a gene product expressed from a promoter regulated by the adjustable-threshold switch and thus forms a feedback loop that causes periodic switching of the adjustable-threshold switch between an “on” state and an “off” state. Multi-state genetic oscillators are useful to express one or more genes of interest in a periodic manner without requiring a periodic application of an external activating agent.

Abstract: A damper unit is provided that is adapted to be positioned in a furnace duct line. The damper unit has a housing which is in communication with a fresh air source and a furnace system. The housing has a damper blade which is moveable between an open position which allows air flow through the housing and a closed position which prevents air flow through the housing. The blade is coupled with a solenoid so that when the solenoid is activated the blade is moved to an open position allowing air flow through the housing. Further, a fan is located in the housing adjacent the damper blade. The fan operates to move air into and out of the housing and across the damper blade when the damper blade is in its open position. In one embodiment, a pair of sealing ridges are provided on the interior of the housing.

Abstract: An anti-slip separator sheet that increases friction and reduces slippage when handling, storing and shipping goods and packages. The sheet is preferably a plastic net with polymer beads protruding from the top and bottom surfaces of the net. The polymer beads are preferably secured to the net by bonding the polymer beads to each other in the openings of the net. The polymer beads protrude from the surfaces of the net, increasing the coefficient of friction. The anti-slip net is used between goods and packages to reduce slippage.