The phase behavior of two types of poly(ethylene oxide)/poly(propylene oxide) (PEO/PPO) copolymers in aqueous solutions was studied by light scattering, viscometry, and infrared spectroscopy. Both the reverse poloxamer (Pluronic 10R5) and the star type poloxamine (Tetronic 90R4) have practically the same PEO/PPO ratio with their hydrophobic blocks (PPO) located in the outer part. The temperatur...

Numerous experimental techniques for the separation of transfer ribonucleic acids have been used successfully in preparing partially purified fractions of several specific tRNAs.1 Many of the existing methods have depended upon the differential solubility of specific tRNAs in complex two-phase systems (I-B), and the separations were achieved by means of countercurrent extraction techniques. Col...

The past decade has assisted to a growing interest in reverse engineering and to the consequent proliferation of papers and experience reports about this subject from both academic and industrial environments. Many types of reverse engineering process components (i.e. methods, algorithms, techniques, procedures, processes model, etc.) have been proposed. To be able to reuse effectively the publ...

Spumaviruses are complex retroviruses whose replication cycle resembles that of hepadnaviruses, especially by a late-occurring reverse transcription step. The possible existence of an early reverse transcription as observed in other retroviruses was not documented. Using real-time quantitative PCR, we addressed directly the kinetics of DNA synthesis during spumavirus infection. An early phase o...

A new, rapid, economical and isocratic reverse phase high performance liquid chromatography (RP-HPLC) method was developed for the determination of eptifibatide acetate, a small synthetic antiplatelet peptide, in bulk drug substance and pharmaceutical dosage forms. The developed method was validated as per of ICH guidelines. The chromatographic separation was achieved isocratically on C18 colum...

Sexual reproduction, typically conceived of as a puzzling feature of eukaryotes, has posed an extraordinary evolutionary challenge in terms of the twofold replicative advantage of asexual over sexual organisms. Here we show mathematically that a greater than twofold cost is paid by retroviruses such as HIV during reverse transcription. For a retrovirus, replication is achieved through RNA rever...

We have investigated the distributions of individually isolated and hydrophilically functionalized single-walled carbon nanotubes (p-SWNTs) in the Pluronic L121-water system at the reverse hexagonal phase using small-angle X-ray scattering (SAXS) and contrast-matched small-angle neutron scattering (SANS) measurements. As the p-SWNT-L121-water system is transitioned from the lamellar phase to th...

The design and synthesis of a new cross-linkable amphiphile is reported. Solutions of the amphiphile in a toluene/water mixture form reverse micelles as indicated by dynamic light scattering and NMR spectroscopy. As indicated by dynamic light scattering, TEM, and NMR spectroscopy data, these reverse micelles can be cross-linked without drastically changing the radius of the reverse micelles. Mi...

Urinary 1-hydroxypyrene is frequently used as a major metabolite and biological indicator of the overall exposure to polycyclic aromatic hydrocarbons. In this study, solid phase extraction was appropriately conditioned with regard to sample pH, sample concentration, loading flow rate, elution solvent, washing solvent, sample volume and sorbent mass. Octadecyl silica cartridge (C<su...