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We quantified the Manning free (uncondensed) counterions fraction θ for dilute aqueous solutions of rodlike polyions: 150 bp DNA fragments, in the presence of a very low concentration of monovalent salt c(salt)<0.05 mM. Conductivity measurements of these solutions for DNA base pair concentration range 0.015≤c≤8 mM were complemented by fluorescence(More)
We report on a detailed characterization of complex dielectric response of Na-DNA aqueous solutions by means of low-frequency dielectric spectroscopy (40 Hz-110 MHz). Results reveal two broad relaxation modes of strength 20<Deltaepsilon(LF)<100 and 5<Deltaepsilon(HF)<20, centered at 0.5 kHz<nu(LF)<70 kHz and 0.1 MHz<nu(HF)<15 MHz. The characteristic length(More)
Ultrathin nanopore membranes based on 2D materials have demonstrated ultimate resolution toward DNA sequencing. Among them, molybdenum disulfide (MoS2) shows long-term stability as well as superior sensitivity enabling high throughput performance. The traditional method of fabricating nanopores with nanometer precision is based on the use of focused(More)
The fundamental length scales in semidilute Na-DNA aqueous solutions have been investigated by dielectric spectroscopy. The low- and the high-frequency relaxation modes are studied in detail. The length scale of the high-frequency relaxation mode at high DNA concentrations can be identified with the de Gennes-Pfeuty-Dobrynin correlation length of(More)
Dielectric spectroscopy is used to investigate fundamental length scales describing the structure of hyaluronic acid sodium salt (Na-HA) semidilute aqueous solutions. In salt-free regime, the length scale of the relaxation mode detected in MHz range scales with HA concentration as c(HA)(-0.5) and corresponds to the de Gennes-Pfeuty-Dobrynin correlation(More)
The charge response in the spin chain and/or ladder compound Sr14-xCaxCu24O41 is characterized by dc resistivity, low-frequency dielectric spectroscopy and optical spectroscopy. We identify a phase transition below which a charge-density wave (CDW) develops in the ladder arrays. Calcium doping suppresses this phase with the transition temperature decreasing(More)
Amino acid sequencing and more detailed structure elucidation analysis of peptides and small proteins is a very difficult task even if state-of-the-art mass spectrometry (MS) is employed. To make this task easier, chemical derivatization methods of the N terminus with 4-sulfophenyl-isothiocyanate (SPITC) or the C terminus with(More)
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