<html><body><div style="font-family: arial,helvetica,sans-serif; font-size: 12pt; color: #000000"><div>Poštovani, podsjećamo na današnji seminar na IF-u u 15h.<br></div><div style="color:#000;font-weight:normal;font-style:normal;text-decoration:none;font-family:Helvetica,Arial,sans-serif;font-size:12pt;" data-mce-style="color: #000; font-weight: normal; font-style: normal; text-decoration: none; font-family: Helvetica,Arial,sans-serif; font-size: 12pt;"><div><br></div><div style="font-family: arial,helvetica,sans-serif; font-size: 12pt; color: #000000" data-mce-style="font-family: arial,helvetica,sans-serif; font-size: 12pt; color: #000000;"><div style="color:#000;font-weight:normal;font-style:normal;text-decoration:none;font-family:Helvetica,Arial,sans-serif;font-size:12pt;" data-mce-style="color: #000; font-weight: normal; font-style: normal; text-decoration: none; font-family: Helvetica,Arial,sans-serif; font-size: 12pt;"><div style="font-family: arial,helvetica,sans-serif; font-size: 12pt; color: #000000" data-mce-style="font-family: arial,helvetica,sans-serif; font-size: 12pt; color: #000000;"><div><p style="margin: 0px; text-align: center; line-height: normal;" data-mce-style="margin: 0px; text-align: center; line-height: normal;" align="center"><b><span style="font-size: 12.0pt; color: black;" data-mce-style="font-size: 12.0pt; color: black;" lang="HR">15. prosinca 2014. (ponedjeljak) u 15:00 sati </span></b><span style="font-size: 12.0pt; font-family: 'Arial','sans-serif'; color: black;" data-mce-style="font-size: 12.0pt; font-family: 'Arial','sans-serif'; color: black;"></span></p><p style="margin: 0px; text-align: center; line-height: normal;" data-mce-style="margin: 0px; text-align: center; line-height: normal;" align="center"><span style="font-size: 12.0pt; color: black;" data-mce-style="font-size: 12.0pt; color: black;" lang="HR">Institut za fiziku, Bijenička cesta 46, predavaonica u III krilu</span><span style="font-size: 12.0pt; font-family: 'Arial','sans-serif'; color: black;" data-mce-style="font-size: 12.0pt; font-family: 'Arial','sans-serif'; color: black;"></span></p><p style="margin: 0px; text-align: center; line-height: normal;" data-mce-style="margin: 0px; text-align: center; line-height: normal;" align="center"><span style="font-size: 12.0pt; color: black;" data-mce-style="font-size: 12.0pt; color: black;" lang="HR"> </span><b><span style="font-size: 16.0pt; color: black;" data-mce-style="font-size: 16.0pt; color: black;" lang="HR"> </span></b><span style="font-size: 12.0pt; font-family: 'Arial','sans-serif'; color: black;" data-mce-style="font-size: 12.0pt; font-family: 'Arial','sans-serif'; color: black;"></span></p><p style="margin: 0px; text-align: center; line-height: normal;" data-mce-style="margin: 0px; text-align: center; line-height: normal;" align="center"><b><span style="font-size: 16.0pt; color: black;" data-mce-style="font-size: 16.0pt; color: black;" lang="HR"><img src="cid:04db44a165756425143cad36916addbfd9912d7a@zimbra" data-mce-src="cid:04db44a165756425143cad36916addbfd9912d7a@zimbra"> </span></b></p><p style="margin: 0px; text-align: center; line-height: normal;" data-mce-style="margin: 0px; text-align: center; line-height: normal;" align="center"><b><span style="font-size: 16.0pt; color: black;" data-mce-style="font-size: 16.0pt; color: black;" lang="HR"></span></b><b><span style="font-size: 16.0pt; color: black;" data-mce-style="font-size: 16.0pt; color: black;" lang="HR">Aleš Omerzu</span></b><span style="font-size: 12.0pt; font-family: 'Arial','sans-serif'; color: black;" data-mce-style="font-size: 12.0pt; font-family: 'Arial','sans-serif'; color: black;"></span></p><p style="margin: 0px; text-align: center; line-height: normal;" data-mce-style="margin: 0px; text-align: center; line-height: normal;" align="center"><br></p><p style="text-align: center; margin: 0px;" data-mce-style="text-align: center; margin: 0px;" align="center"><span style="font-family: arial,helvetica,sans-serif;" data-mce-style="font-family: arial,helvetica,sans-serif;" lang="EN-GB">Jozef Stefan Institute, Ljubljana</span></p><p style="margin: 0px; text-align: center; line-height: normal;" data-mce-style="margin: 0px; text-align: center; line-height: normal;" align="center"><span style="color: black;" data-mce-style="color: black;" lang="HR"></span><span style="font-size: 12.0pt; font-family: 'Arial','sans-serif'; color: black;" data-mce-style="font-size: 12.0pt; font-family: 'Arial','sans-serif'; color: black;"></span><b><span style="font-size: 16.0pt; color: black;" data-mce-style="font-size: 16.0pt; color: black;" lang="HR"> <br></span></b></p><p style="margin: 0px; text-align: center; line-height: normal;" data-mce-style="margin: 0px; text-align: center; line-height: normal;" align="center"><span style="font-family: arial,helvetica,sans-serif;" data-mce-style="font-family: arial,helvetica,sans-serif;"><b><span style="font-size: 16pt; color: black;" data-mce-style="font-size: 16pt; color: black;" lang="HR"><b><span style="font-size: 20pt;" data-mce-style="font-size: 20pt;" lang="EN-GB">DNA as a 1D Electronic System</span></b></span></b></span><span style="font-size: 12.0pt; font-family: 'Arial','sans-serif'; color: black;" data-mce-style="font-size: 12.0pt; font-family: 'Arial','sans-serif'; color: black;"></span></p><p style="margin: 0px; text-align: center; line-height: normal;" data-mce-style="margin: 0px; text-align: center; line-height: normal;" align="center"><b><span style="font-size: 16.0pt; color: black;" data-mce-style="font-size: 16.0pt; color: black;"> </span></b><span style="font-size: 12.0pt; font-family: 'Arial','sans-serif'; color: black;" data-mce-style="font-size: 12.0pt; font-family: 'Arial','sans-serif'; color: black;"></span></p><p style="margin: 0px; text-align: justify; line-height: normal;" data-mce-style="margin: 0px; text-align: justify; line-height: normal;"><span style="font-size: 12.0pt; color: black;" data-mce-style="font-size: 12.0pt; color: black;" lang="HR"> </span></p><p style="margin: 0px; text-align: justify; line-height: normal;" data-mce-style="margin: 0px; text-align: justify; line-height: normal;"><span style="font-size: 12.0pt; color: black;" data-mce-style="font-size: 12.0pt; color: black;" lang="HR">With the advent of nanoscience and nanotechnology in the late 1990’s a research activity on DNA electronic properties sharply increased. It was mainly due to the unique properties of DNA single strands - complementarity and recombination ability. They enable formation of complex nanostructures by self-assembly which could be utilized in nanoelectronics. Early two-contact measurements of conductivity on single molecules or bundles of few DNA molecules gave discrepant results which spanned the whole spectrum of conductivities from insulating and semiconducting to conducting [1]. However, it was shown lately that DNA is a very poor conductor of electricity at distances longer than ~10 nm [2]. The reason for that lies in DNA electronic structure. Similarly to quasi 1D organic conductors, DNA consist of planar stacks of heterocyclic aromatic molecules with intrastack distances of ~ 3Å, where the <span style="font-size: 12.0pt; color: black;" data-mce-style="font-size: 12.0pt; color: black;" lang="HR">π</span>-π overlap of molecular HOMO and LUMO orbitals forms the valence and the conduction band, respectively. But in contrast to 1D organic conductors, DNA lacks counterions which would partially fill a conduction band of the 1D stack. Apparently, to improve conducting properties of DNA one should add either additional electrons in the conducting band or additional holes in the valence band. A possibility of electron doping of DNA emerged with discovery of M-DNA [3], a complex which DNA spontaneously forms with transition metal cations, Co2+, Ni2+ and Zn2+. Fluorescence quenching and electrochemical measurements in solution have shown a strong increase in electron transfer rates upon formation of the M-DNA complex. Measurements of M-DNA electric conductivity in the solid state have shown significant differences between a semiconducting behaviour in DNA and a metallic-like in M-DNA. Still, the mechanism of improved conductivity of M-DNA was not clear. In order to detect free charge carriers in M-DNA we performed ESR measurements on a dry Zn-DNA complex [4]. Additional electrons in Zn-DNA result in a strong, broad and asymmetric ESR signal. The shape and position of the ESR line suggest that unpaired electrons could be delocalized thus explaining the metallic nature of M-DNA. Later measurements of temperature dependence of the ESR parameters – line-width, resonant field and ESR intensity, as well the microwave absorption, have confirmed that the additional electrons introduced into the LUMO levels in M-DNA form a strongly correlated 1D system of delocalized electrons.</span><span style="font-size: 12.0pt; font-family: 'Arial','sans-serif'; color: black;" data-mce-style="font-size: 12.0pt; font-family: 'Arial','sans-serif'; color: black;"></span></p><p style="margin: 0px; text-align: justify; line-height: normal;" data-mce-style="margin: 0px; text-align: justify; line-height: normal;"><span style="font-size: 12.0pt; color: black;" data-mce-style="font-size: 12.0pt; color: black;" lang="HR"><br></span></p><p style="margin: 0px; text-align: justify; line-height: normal;" data-mce-style="margin: 0px; text-align: justify; line-height: normal;"><span style="font-size: 12.0pt; color: black;" data-mce-style="font-size: 12.0pt; color: black;" lang="HR"><br>[1] R. G. Endres, D. L. Cox, R. R. P. Singh, Rev. Mod. Phys. 76, 195 (2004).<br>[2] A. J. Storm, J. van Noort, S de Vries, C. Dekker, Appl. Phys. Lett. 79, 3881 (2001)<br>[3] P. Aich et al., J. Mol. Biol. 294, 477 (1999).<br>[4] A. Omerzu et al., Phys. Rev. Lett. 104, 156804 (2010). </span></p><p style="margin: 0px; text-align: right; line-height: normal;" data-mce-style="margin: 0px; text-align: right; line-height: normal;" align="right"><span style="color: black;" data-mce-style="color: black;" lang="HR"> </span><span style="font-size: 12.0pt; font-family: 'Arial','sans-serif'; color: black;" data-mce-style="font-size: 12.0pt; font-family: 'Arial','sans-serif'; color: black;"></span><span style="color: black;" data-mce-style="color: black;" lang="HR"> <br></span></p><p style="margin: 0px; text-align: right; line-height: normal;" data-mce-style="margin: 0px; text-align: right; line-height: normal;" align="right"><span style="color: black;" data-mce-style="color: black;" lang="HR"> </span></p><p style="margin: 0px; text-align: right; line-height: normal;" data-mce-style="margin: 0px; text-align: right; line-height: normal;" align="right"><span style="color: black;" data-mce-style="color: black;" lang="HR">Voditelji seminara IF-a: Nikša Krstulović i Osor Barišić</span><span style="font-size: 12.0pt; font-family: 'Arial','sans-serif'; color: black;" data-mce-style="font-size: 12.0pt; font-family: 'Arial','sans-serif'; color: black;"></span></p></div></div></div></div></div></div></body></html>