The present invention provides methods for screening drugs inhibiting the expression of OSF-2 gene or the production or function of the protein encoded thereby and therapeutic agents for heart failure having such effects. The power source unit includes a secondary battery, and a chargedischarge circuit for controlling charge and discharge of the secondary battery. 45Tm22; the half-value width Th of the peak top of its elution curve obtained in programmed-temperature fractionation is Th5; and its intrinsic viscosity measured in a solvent of tetralin at 135 C. The controller is further configured to determine an aging condition for the at least one first switch for the first phase based on an equivalent time, Teq of the at least one first switch, wherein Teq corresponds to an amount of time the at least one first switch is active and on an operating temperature of the at least one first switch while the at least one first switch is active. In one embodiment, unknown sources are spatially grouped to produce a system interaction matrix with block factors of low rank within a given error tolerance and the unknown sources are determined from compressed forms of the factors. These electrical devices should be mounted to a support to keep order within such electrical or electronic systems and thus achieve systems comprising electrical devices with a reproducible output and which are reliable and easy to maintain.