Ultraviolet absorption methods for the study of nucleic acids have become increasingly useful since the quantitative relationships between nucleic acids and their absorption of ultraviolet light have been shown by Caspersson (1). For example, ultraviolet measurements provide a rapid and simple means of determining the total nucleic acid (TNA) value which may be used to verify the TNA value arri...

Expression of the tryptophanase (tna) operon in Escherichia coli is regulated by catabolite repression and transcription attenuation. Elevated levels of tryptophan induce transcription antitermination at one or more Rho factor-dependent termination sites in the leader region of the operon. Induction requires translation of a 24-residue coding region, tnaC, located in the 319-nucleotide transcri...

BACKGROUND Transient nonfocal neurological symptoms may serve as markers of cardiac dysfunction. We assessed whether serum N-terminal pro-brain natriuretic peptide (NT-proBNP) levels, a biomarker of cardiac disease, are increased in patients with transient ischemic attack (TIA) accompanied by nonfocal symptoms and in patients with attacks of nonfocal symptoms (transient neurological attack [TNA...

The liquid crystal octylcyanobiphenyl (8CB) was doped with the chiral agent CB15 and spin-coated onto a substrate treated for planar alignment of the director, resulting in a film of thickness several hundred nm in the smectic-A phase. In both doped and undoped samples, the competing boundary conditions - planar alignment at the substrate and vertical alignment at the free surface - cause the l...