Most challenging in the development of DNA sensors is the ability to distinguish between fully complementary target ssDNA (single-strand DNA) and 1-mismatch ssDNA. To deal with this problem, we performed impedance spectroscopy on DNA-functionalized nanocrystalline diamond (NCD) layers during hybridization and denaturation. In both reactions, a difference in behavior was observed for 1-mismatch target DNA and complementary target DNA in real-time. During real-time hybridization, a decrease of the impedance was observed at lower frequencies when the complementary target DNA was added, while the addition of 1-mismatch target ssDNA caused no significant change. Fitting these results to an electrical circuit demonstrates that this is correlated with a decrease of the depletion zone in the space charge region of the diamond. During real-time denaturation, differentiation between 1-mismatch and complementary target DNA was possible at higher frequencies. Denaturation of complementary DNA showed the longest exponential decay time of the impedance, while the decay time during 1-mismatch denaturation was the shortest. The real-time hybridization and denaturation experiments were carried out on different NCD samples in various buffer solutions at temperatures between 20 and 80 degrees C. It was revealed that the best results were obtained using a Microhyb hybridization buffer at 80 degrees C and 10x PCR buffer at 30 degrees C for hybridization and 0.1 M NaOH at temperatures above 40 degrees C for denaturation. We demonstrate that the combination of real-time hybridization spectra and real-time denaturation spectra yield important information on the type of target. This approach may allow a reliable identification of the mismatch sequence, which is the most biologically relevant.
Fine structure in the o. decay of mass-separated Pb and Hg has been studied at the GSI on-line mass separator. Alpha singles spectra as well as a-x-t and a-e-t coincidence events were collected. The o. decay of Pb revealed feeding to a low-lying 0+ state at 328(12) keV inHg.This state can be interpreted as being the bandhead of the deformed rotational band observed previously in in-beam studies. In the a decay of Hg, feeding towards the Srst excited 2+ state at 153 keV and the 0~+ state at 478 keV in Pt was observed. The hindrance factor of the a decay towards the excited 0+ state gives information about the particle-hole character of the states connected in the a decay. A two-level mixing calculation is introduced. From the fixing in Pt and the a-decay hindrance factors, small mixing is deduced for ground states of neutron-de6cient Hg and Pb nuclei.
large variation in the hindrance factors of the a decay to the excited 0+ state is a proof for the persistence of the Z 82 shell closure at the neutron-deficient side. Comparing the reduced widths of the a decays to the ground and excited states offers a unique way to probe the proton particle-hole character of the 0+ states in this region.PACS numbers: 23.60.+e, 21.60. Cs, 27.70.+q, 27.80.+w Alpha decay, although one of the oldest study objects in nuclear physics, remains an intriguing decay mode.The explanation of the striking relation between the adecay half-life and the a-decay energy, known as the Geiger-Nuttall law, was one of the prominent successes of quantum mechanics [1,2]. Later on, Rasmussen [3] proposed to extract from the partial a-decay half-lives and the a-decay energies, the reduced a widths (8 ), a
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