Disclosed is a rule assembly having a housing, a reel rotatably mounted in the housing, an elongated blade wound on the reel and extendable through an opening in the housing, and a permanent end hook member attached to the elongated blade with a first hook portion. The invention also applies to strained layers in other electronic devices such as strained SiGe, Si in MOS applications, vertical thin film transistors, and a variety of other electronic device types. A compile unit is formed from the extracted source code and metadata. Electroporation allows optimal transfection of nucleic acids into cells by minimizing cell death while maximizing transfection efficiency.