Abstract: An engine noise reduction system includes a spring-biased valve (106) disposed in an engine air inlet (100). When the engine (104) is operating in a first mode that draws an increased amount of air through the inlet (100), vacuum pressure generated by the increased air flow overcomes the biasing force in the spring and forces the valve (106) open, maximizing air flow through the inlet. When the engine (104) operates in a second mode that requires less air, the biasing force overcomes the reduced vacuum pressure in the inlet (100), closing the valve (106) and thereby restricting the amount of air flowing through the inlet (100). The reduced airflow area changes the acoustic impedance for transmitting engine noise through the inlet (100).

Abstract: Described are compositions and methods which allow for the efficient addition of a defined sequence at the 3'-end of a full-length cDNA in the course of first-strand cDNA synthesis from an mRNA template. A cDNA synthesis primer that is capable of annealing to mRNA is used to prime the first strand synthesis reaction. An oligonucleotide that is linked to the 5'-end of the mRNA serves as a short, extended template such that when the reverse transcriptase enzyme reaches the 5'-end of the mRNA, the enzyme switches templates and proceeds to transcribe through the end of the linked oligonucleotide. As a result, the single-stranded cDNA product which corresponds to the full-length mRNA, will have at the 3'-end a defined sequence which is complementary to the linked oligonucleotide. A conservative element in the oligonucleotide sequence responsible for this reaction can include 3 to 5 guanylic acid residues at the 3'-end of the oligonucleotide.

Abstract: The present invention pertains to methods for the synthesis and cloning of full-length cDNA, or cDNA fragments, that correspond to the complete sequence of 5'-ends of mRNA molecules. The method of the present invention comprises contacting RNA with a cDNA synthesis primer which can anneal to RNA, a suitable enzyme which possesses reverse transcriptase activity, and a template switching oligonucleotide under conditions sufficient to permit the template-dependent extension of the primer to generate an mRNA-cDNA hybrid. The template switching oligonucleotide hybridizes to the CAP site at the 5'-end of the RNA molecule and serves as a short, extended template for CAP-dependent extension of the 3'-end of the ss cDNA that is complementary to the template switching oligonucleotide.