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The frequency-dependent, complex refractive indices for carvone in the mid-infrared from 750 to 5000 cm(super -1) is inverted from the Fourier transform extinction spectra of laboratory-generated aerosols recorded at room temperature. The indices are obtained with the help of Mie inversion of aerosol extinction spectra.

An alternative approach to imitation of lung surfactant proteins B and C (SP-B and SP-C), two helical and amphiphilic proteins that are critical for normal respiration, based on sequence-random copolymers containing cationic and lipophilic subunits is described. The study provides evidence for the sequence-random copolymers that could mimic the in vitro surface-active behavior of lung surfactant proteins in a mixed lipid film and their useful application for developing a lung surfactant replacement.

The surface activities of six different helical peptoid analogues of amphipathic 25mer from the amino terminus (SP-[B.sub.(1-25)]) is compared to investigate the importance of mimicking its N-terminal insertion domain as well as its two arginine residues, both thought to be important for the peptide's proper function. SP-B is one of two helical, amphiphatic proteins critical for the biophysical functioning of lung surfactant (LS) and hence is an important therapeutic protein.

Peptoids are a developing class of peptide-like oligomers originally invented for drug discovery in the early 1990s. While peptides hold great promise for therapeutic applications, current development of peptide-based pharmaceuticals is hindered by their potential for misfolding and aggregation, and particularly, for rapid in vivo degradation post-administration. Researchers have investigated alternative peptide-like constructs that may be able to circumvent such complications. Peptoids comprise a peptide-based backbone and N-substituted glycines for side chain residues, resulting in complete protease-resistance. Synthesis of peptoid sequences up to 50 units in length allows for controlled sequence composition and incorporation of diverse side chain chemistries. Though the landscape of peptoid structure is not clearly defined, secondary, tertiary, loop, turn, and random structures have been identified. As protease-resistant isomers of peptides, peptoids are being developed as versatile molecular tools in biochemistry and biophysics, and are becoming attractive candidates for therapeutic and diagnostic applications. Peptoids have thus far demonstrated bioactivity as protein mimics and as replacements for small molecule drugs. In this review, we discuss the most recent advances in peptoid research on the therapeutic front in the last few years, including in vitro and in vivo studies in the fields of lung surfactant therapy, antimicrobial agents, diagnostics, and cancer. We particularly focus on the biophysical activity of lipid-associated peptoids and their potential therapeutic applications.