Microtubules (MTs) are important cytoskeletal polymers engaged in a number of specific cellular activities including the traffic of organelles using motor proteins, cellular architecture and motility, cell division and a possible participation in information processing within neuronal functioning. How MTs operate and process electrical information is still largely unknown. In this paper we investigate the conditions enabling MTs to act as electrical transmission lines for ion flows along their lengths. We introduce a model in which each tubulin dimer is viewed as an electric element with a capacitive, inductive and resistive characteristics arising due to polyelectrolyte nature of MTs. Based on Kirchhoff's laws taken in the continuum limit, a nonlinear partial differential equation is derived and analyzed. We demonstrate that it can be used to describe the electrostatic potential coupled to the propagating localized ionic waves.

Spectra of possible phonon states, as well as thermodynamic characteristics of nanocrystals (ultrathin film and quantum wire) of simple cubic crystalline structure are analyzed in this paper, using the method of two-time dependent Green functions. From energy spectra and internal energy of the system the thermal capacitance of these structures in low temperature region is found. The temperature behavior of specific heat is compared to that of corresponding bulk structure. It is shown that at extremely low temperatures thermal capacitance of quantum wire is considerably lower than the thermal capacitance of film as well as the bulk sample. Consequences of this fact are discussed in detail and its influence to thermodynamic properties of materials is estimated.

In our recent paper (SatariT et al. 2009), the Introduction section contained statements regarding the C-terminal tails that have inadvertently been included without properly citing the source of this information provided. In particular, the passage given below should be attributed to Georgiev et al. (2004) who almost 5 years earlier correctly pointed out the importance of the C-terminal tail sequence and structure. "Each tubulin monomer of the MT lattice has a short C-terminal helix H12 followed by a highly acidic amino acid sequence projecting out of the MT outer surface called a tubulin tail (TT). The TTs are short polypeptide sequences of 4-5 nm length when completely outstretched, protruding from the MT surface into the solution. They are essential for MT interactions with MT associated proteins and motor proteins. Jimenez et al. (1999) determined the helicity of a (404-451) and b (394-445) tubulin C-terminal recombinant peptides with the use of NMR spectroscopy. The -tubulin TT amino acid sequence is EEVGADSVEGEGEEEGEEY. The -tubulin tail is 19 amino acids long and possesses 10 negatively charged residues. The situation in the tubulin C-terminal domain is even more interesting. Jimenez et al. found a helix there, which is 9 amino acids longer than in tubulin. This suggests an extension into the protein, supporting the possibility of a functional coil-to-helix transition at the TT zone. The -tubulin TT helix H12 is formed by amino acid residues (408-431) but it seems that the reversible transition between coil and the helix comprising the last 9 amino acid residues (423-431) from -tubulin TT helix (with sequence QQYQDATAD) could either increase or decrease the length of H12, at the same time changing the -TT length.The corresponding residues (432-445) contain the 14 amino acids EQGEFEEEEGEDEA with 9 negatively charged residues (E, A)".The omission of the proper reference and citation has not been intentional on our part but we deeply regret not having given proper care and attention to the source of the statement and wish to apologize to the authors for it. The online version of the original article can be found under References

A microscopic theory of dielectrical properties of thin molecular films, i.e. quasi 2D systems bounded by two surfaces parallel to XY planes was formulated. Harmonic exciton states were calculated using the method of two-time, retarded, temperature dependent Green's functions. It has been shown that two types of excitations can occur: bulk and surface exciton states. Analysis of the optical properties of these crystalline systems for low exciton concentration shows that the permittivity strongly depends on boundary parameters and the thickness of the film. Conditions for the appearance of localized exciton states have been especially analyzed.

Phonon spectra and allowed phonon states, as well as thermodynamic characteristics of nanowires of simple cubic crystalline structure, are analyzed using the method of two-time dependent Green's functions, adjusted to bounded crystalline structures. Poles of Green's functions, defining phonon spectra, can be found by solving of the secular equation. For different boundary parameters, this problem is presented graphically. The presence of boundaries as well as the change of boundary parameters leads to appearance of new properties of low dimensional structures (thin film and nanowire). The most important feature is that beside allowed energy zones (which are continuous as in the bulk structure), zones of forbidden states appear. Different values of boundary parameters lead to appearance of lower and upper energy gaps, or dispersion branches spreading out of bulk energy zone. The correlation with spectra of phonons in corresponding unbounded structures is maintained in the work. Determination of phonon spectra and allowed phonon energies has great importance for kinetic and thermodynamic properties of semiconductive nanostructures and devices. The temperature behavior of nanowire thermal capacitance is compared to that of bulk structures. It is shown that at extremely low temperature nanowire thermal capacitance is considerably lower than the thermal capacitance of bulk sample. It was discussed what are the consequences of this fact to the thermal, conducting and superconducting properties of materials.