Showing papers by "Tokyo University of Science published in 2010"

f(R) theories

Abstract: Over the past decade, f(R) theories have been extensively studied as one of the simplest modifications to General Relativity. In this article we review various applications of f(R) theories to cosmology and gravity - such as inflation, dark energy, local gravity constraints, cosmological perturbations, and spherically symmetric solutions in weak and strong gravitational backgrounds. We present a number of ways to distinguish those theories from General Relativity observationally and experimentally. We also discuss the extension to other modified gravity theories such as Brans-Dicke theory and Gauss-Bonnet gravity, and address models that can satisfy both cosmological and local gravity constraints.

Dark Energy: Theory and Observations

Abstract: 1. Overview 2. Expansion history of the universe 3. Correlation function and power spectrum 4. Basics of cosmological perturbation theory 5. Observational evidence of dark energy 6. Cosmological constant 7. Dark energy as a modified form of matter I: quintessence 8. Dark energy as a modified form of matter II 9. Dark energy as a modification of gravity 10. Cosmic acceleration without dark energy 11. Dark energy and linear cosmological perturbations 12. Non-linear cosmological perturbations 13. Statistical methods in cosmology 14. Future observational constraints on the nature of dark energy 15. Conclusion and outlook 16. Answers to the problems 17. Mathematical appendix Index.

Reducing Graphene Oxide on a Visible-Light BiVO4 Photocatalyst for an Enhanced Photoelectrochemical Water Splitting

Abstract: Bismuth vanadate (BiVO4) is incorporated with reduced graphene oxide (RGO) using a facile single-step photocatalytic reaction to improve its photoresponse in visible light. Remarkable 10-fold enhancement in photoelectrochemical water splitting reaction is observed on BiVO4−RGO composite compared with pure BiVO4 under visible illumination. This improvement is attributed to the longer electron lifetime of excited BiVO4 as the electrons are injected to RGO instantly at the site of generation, leading to a minimized charge recombination. Improved contact between BiVO4 particles with transparent conducting electrode using RGO scaffold also contributes to this photoresponse enhancement.

f(R) theories

Abstract: Over the past decade, f(R) theories have been extensively studied as one of the simplest modifications to General Relativity. In this article we review various applications of f(R) theories to cosmology and gravity - such as inflation, dark energy, local gravity constraints, cosmological perturbations, and spherically symmetric solutions in weak and strong gravitational backgrounds. We present a number of ways to distinguish those theories from General Relativity observationally and experimentally. We also discuss the extension to other modified gravity theories such as Brans-Dicke theory and Gauss-Bonnet gravity, and address models that can satisfy both cosmological and local gravity constraints.

NetPath: a public resource of curated signal transduction pathways

Abstract: We have developed NetPath as a resource of curated human signaling pathways. As an initial step, NetPath provides detailed maps of a number of immune signaling pathways, which include approximately 1,600 reactions annotated from the literature and more than 2,800 instances of transcriptionally regulated genes - all linked to over 5,500 published articles. We anticipate NetPath to become a consolidated resource for human signaling pathways that should enable systems biology approaches.

Cilostazol for prevention of secondary stroke (CSPS 2): an aspirin-controlled, double-blind, randomised non-inferiority trial.

Abstract: Summary Background The antiplatelet drug cilostazol is efficacious for prevention of stroke recurrence compared with placebo. We designed the second Cilostazol Stroke Prevention Study (CSPS 2) to establish non-inferiority of cilostazol versus aspirin for prevention of stroke, and to compare the efficacy and safety of cilostazol and aspirin in patients with non-cardioembolic ischaemic stroke. Methods Patients aged 20–79 years who had had a cerebral infarction within the previous 26 weeks were enrolled at 278 sites in Japan and allocated to receive 100 mg cilostazol twice daily or 81 mg aspirin once daily for 1–5 years. Patients were allocated according to a computer-generated randomisation sequence by means of a dynamic balancing method using patient information obtained at registration. All patients, study personnel, investigators, and the sponsor were masked to treatment allocation. The primary endpoint was the first occurrence of stroke (cerebral infarction, cerebral haemorrhage, or subarachnoid haemorrhage). The predefined margin of non-inferiority was an upper 95% CI limit for the hazard ratio of 1·33. Analyses were by full-analysis set. This trial is registered with ClinicalTrials.gov, number NCT00234065. Findings Between December, 2003, and October, 2006, 2757 patients were enrolled and randomly allocated to receive cilostazol (n=1379) or aspirin (n=1378), of whom 1337 on cilostazol and 1335 on aspirin were included in analyses; mean follow-up was 29 months (SD 16). The primary endpoint occurred at yearly rates of 2·76% (n=82) in the cilostazol group and 3·71% (n=119) in the aspirin group (hazard ratio 0·743, 95% CI 0·564–0·981; p=0·0357). Haemorrhagic events (cerebral haemorrhage, subarachnoid haemorrhage, or haemorrhage requiring hospital admission) occurred in fewer patients on cilostazol (0·77%, n=23) than on aspirin (1·78%, n=57; 0·458, 0·296–0·711; p=0·0004), but headache, diarrhoea, palpitation, dizziness, and tachycardia were more frequent in the cilostazol group than in the aspirin group. Interpretation Cilostazol seems to be non-inferior, and might be superior, to aspirin for prevention of stroke after an ischaemic stroke, and was associated with fewer haemorrhagic events. Therefore, cilostazol could be used for prevention of stroke in patients with non-cardioembolic stroke. Funding Otsuka Pharmaceutical.

A Single-Phase Multilevel Inverter Using Switched Series/Parallel DC Voltage Sources

Abstract: A novel multilevel inverter with a small number of switching devices is proposed. It consists of an H-bridge and an inverter which outputs multilevel voltage by switching the dc voltage sources in series and in parallel. The proposed inverter can output more numbers of voltage levels in the same number of switching devices by using this conversion. The number of gate driving circuits is reduced, which leads to the reduction of the size and power consumption in the driving circuits. The total harmonic of the output waveform is also reduced. The proposed inverter is driven by the hybrid modulation method. In this paper, the circuit configuration, theoretical operation, Fourier analysis, simulation results with MATLAB/SIMULINK, and experimental results are shown. The experimental results accorded with the simulation results.

Modified gravity models of dark energy

Abstract: We review the recent progress for modified gravity models of dark energy – including f(R) gravity, scalar-tensor theories, and braneworld models.

Cosmology of a Covariant Galileon Field

Abstract: We study the cosmology of a covariant scalar field respecting a Galilean symmetry in flat space-time. We show the existence of a tracker solution that finally approaches a de Sitter fixed point responsible for cosmic acceleration today. The viable region of model parameters is clarified by deriving conditions under which ghosts and Laplacian instabilities of scalar and tensor perturbations are absent. The field equation of state exhibits a peculiar phantomlike behavior along the tracker, which allows a possibility to observationally distinguish the Galileon gravity from the cold dark matter model with a cosmological constant.

Isolation, structure, and stability of a dodecanethiolate-protected Pd1Au24 cluster

Abstract: A dodecanethiolate-protected Pd1Au24(SC12H25)18 cluster, which is a mono-Pd-doped cluster of the well understood magic gold cluster Au25(SR)18, was isolated in high purity using solvent fractionation and high-performance liquid chromatography (HPLC) after the preparation of dodecanethiolate-protected palladium–gold bimetal clusters. The cluster thus isolated was identified as the neutral [Pd1Au24(SC12H25)18]0 from the retention time in reverse phase columns and by elemental analyses. The LDI mass spectrum of [Pd1Au24(SC12H25)18]0 indicates that [Pd1Au24(SC12H25)18]0 adopts a similar framework structure to Au25(SR)18, in which an icosahedral Au13 core is protected by six [–S–Au–S–Au–S–] oligomers. The optical absorption spectrum of [Pd1Au24(SC12H25)18]0 exhibits peaks at ∼690 and ∼620 nm, which is consistent with calculated results on [Pd1@Au24(SC1H3)18]0 in which the central gold atom of Au25(SC1H3)18 is replaced with Pd. These results strongly indicate that the isolated [Pd1Au24(SC12H25)18]0 has a core–shell [Pd1@Au24(SC12H25)18]0 structure in which the central Pd atom is surrounded by a frame of Au24(SC12H25)18. Experiments on the stability of the cluster showed that Pd1@Au24(SC12H25)18 is more stable against degradation in solution and laser dissociation than Au25(SC12H25)18. These results indicate that the doping of a central atom is a powerful method to increase the stability beyond the Au25(SR)18 cluster.

A Novel Factor FLOURY ENDOSPERM2 Is Involved in Regulation of Rice Grain Size and Starch Quality

Abstract: Rice (Oryza sativa) endosperm accumulates a massive amount of storage starch and storage proteins during seed development. However, little is known about the regulatory system involved in the production of storage substances. The rice flo2 mutation resulted in reduced grain size and starch quality. Map-based cloning identified FLOURY ENDOSPERM2 (FLO2), a member of a novel gene family conserved in plants, as the gene responsible for the rice flo2 mutation. FLO2 harbors a tetratricopeptide repeat motif, considered to mediate a protein–protein interactions. FLO2 was abundantly expressed in developing seeds coincident with production of storage starch and protein, as well as in leaves, while abundant expression of its homologs was observed only in leaves. The flo2 mutation decreased expression of genes involved in production of storage starch and storage proteins in the endosperm. Differences between cultivars in their responsiveness of FLO2 expression during high-temperature stress indicated that FLO2 may be involved in heat tolerance during seed development. Overexpression of FLO2 enlarged the size of grains significantly. These results suggest that FLO2 plays a pivotal regulatory role in rice grain size and starch quality by affecting storage substance accumulation in the endosperm.

Novel Stannite-type Complex Sulfide Photocatalysts AI2-Zn-AIV-S4 (AI = Cu and Ag; AIV = Sn and Ge) for Hydrogen Evolution under Visible-Light Irradiation

Abstract: Photophysical properties and photocatalytic activities for H2 evolution of the series of stannite-type complex sulfides AI2-Zn-AIV-S4 (AI = Cu and Ag; AIV = Sn and Ge) were studied. Diffuse reflection spectra and the plane-wave-based density functional theory (DFT) calculation suggested that the conduction bands were made up of Ge4s4p or Sn5s5p with S3p orbitals, while the valence bands consisted of Cu3d and Ag4d with S3p orbitals. The constituting elements of AI and AIV affected the photophysical and photocatalytic properties. Ru cocatalyst-loaded Cu2ZnGeS4, Ag2ZnGeS4, and Ag2ZnSnS4 showed high activities for photocatalytic H2 evolution from an aqueous Na2S+K2SO3 solution under visible-light irradiation. Combination of Cu and Ag made it possible that the CuAgZnSnS4 photocatalyst with a narrow band gap (1.4 eV) utilized a wide range of visible light for the H2 evolution.

Photoelectrochemical water splitting using visible-light-responsive BiVO4 fine particles prepared in an aqueous acetic acid solution

Abstract: Fine BiVO4 particles with a tetragonal scheelite structure (s-t) were synthesized from Bi2O3 and V2O5 in an aqueous acetic acid solution. The crystal phase of BiVO4 changed from s-t to monoclinic scheelite structure (s-m) by calcination at 673 K. The fine BiVO4 photocatalysts showed O2 evolution from an aqueous silver nitrate solution and methylene blue decoloration under visible light irradiation. BiVO4(s-m) electrodes were readily prepared by pasting the obtained fine BiVO4(s-t) particles on FTO plates and subsequently calcining at 673 K. The BiVO4 electrode gave an excellent anodic photocurrent with 12% of an IPCE at 440 nm at 1.5 V vs. Ag/AgCl. A wet photovoltaic cell consisting of the BiVO4 photoelectrode and a Pt counter electrode was constructed for water splitting. H2 and O2 evolved from water with an externally applied bias smaller than 1.23 V vs. the Pt counter electrode under visible light and simulated sunlight irradiation.

Effects of Low-Intensity Cycle Training with Restricted Leg Blood Flow on Thigh Muscle Volume and VO2MAX in Young Men

Abstract: Concurrent improvements in aerobic capacity and muscle hypertrophy in response to a single mode of training have not been reported. We examined the effects of low-intensity cycle exercise training with and without blood flow restriction (BFR) on muscle size and maximum oxygen uptake (VO2max). A group of 19 young men (mean age ± SD: 23.0 ± 1.7 years) were allocated randomly into either a BFR-training group (n=9, BFR-training) or a non-BFR control training group (n=10, CON-training), both of which trained 3 days/wk for 8 wk. Training intensity and duration were 40% of VO2max and 15 min for the BFR-training group and 40% of VO2max and 45 min for the CON-training group. MRI-measured thigh and quadriceps muscle cross-sectional area and muscle volume increased by 3.4-5.1% (P < 0.01) and isometric knee extension strength tended to increase by 7.7% (p < 0.10) in the BFR-training group. There was no change in muscle size (~0.6%) and strength (~1.4%) in the CON-training group. Significant improvements in VO2max (6.4%) and exercise time until exhaustion (15.4%) were observed in the BFR-training group (p < 0.05) but not in the CON-training group (-0.1 and 3. 9%, respectively). The results suggest that low-intensity, short-duration cycling exercise combined with BFR improves both muscle hypertrophy and aerobic capacity concurrently in young men. Key points Concurrent improvements in aerobic capacity and muscle hypertrophy in response to a single mode of training have not been reported. In the present study, low-intensity (40% of VO2max) cycle training with BFR can elicit concurrent improvement in muscle hypertrophy and aerobic capacity.

The ASTRO-H mission

Abstract: The joint JAXA/NASA ASTRO-H mission is the sixth in a series of highly successful X-ray missions initiated by the Institute of Space and Astronautical Science (ISAS). ASTRO-H will investigate the physics of the high-energy universe by performing high-resolution, high-throughput spectroscopy with moderate angular resolution. ASTRO-H covers very wide energy range from 0.3 keV to 600 keV. ASTRO-H allows a combination of wide band X-ray spectroscopy (5-80 keV) provided by multilayer coating, focusing hard X-ray mirrors and hard X-ray imaging detectors, and high energy-resolution soft X-ray spectroscopy (0.3-12 keV) provided by thin-foil X-ray optics and a micro-calorimeter array. The mission will also carry an X-ray CCD camera as a focal plane detector for a soft X-ray telescope (0.4-12 keV) and a non-focusing soft gamma-ray detector (40-600 keV) . The micro-calorimeter system is developed by an international collaboration led by ISAS/JAXA and NASA. The simultaneous broad bandpass, coupled with high spectral resolution of ΔE ~7 eV provided by the micro-calorimeter will enable a wide variety of important science themes to be pursued.

Preparation of Highly Crystalline TiO2 Nanostructures by Acid-assisted Hydrothermal Treatment of Hexagonal-structured Nanocrystalline Titania/Cetyltrimethyammonium Bromide Nanoskeleton

Abstract: Highly crystalline TiO2 nanostructures were prepared through a facile inorganic acid-assisted hydrothermal treatment of hexagonal-structured assemblies of nanocrystalline titiania templated by cetyltrimethylammonium bromide (Hex-ncTiO2/CTAB Nanoskeleton) as starting materials. All samples were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The influence of hydrochloric acid concentration on the morphology, crystalline and the formation of the nanostructures were investigated. We found that the morphology and crystalline phase strongly depended on the hydrochloric acid concentrations. More importantly, crystalline phase was closely related to the morphology of TiO2 nanostructure. Nanoparticles were polycrystalline anatase phase, and aligned nanorods were single crystalline rutile phase. Possible formation mechanisms of TiO2 nanostructures with various crystalline phases and morphologies were proposed.

Observational constraints on Galileon cosmology

Abstract: We study the cosmology of a covariant Galileon field $\ensuremath{\phi}$ with five covariant Lagrangians and confront this theory with the most recent cosmological probes: the type Ia supernovae data (Constitution and Union2 sets), cosmic microwave background (WMAP7), and the baryon acoustic oscillations (SDSS7). In the Galileon cosmology with a late-time de Sitter attractor, there is a tracker that attracts solutions with different initial conditions to a common trajectory. Including the cosmic curvature $K$, we place observational constraints on two distinct cases: (i) the tracker, and (ii) the generic solutions to the equations of motion. We find that the tracker solution can be consistent with the individual observational data, but it is disfavored by the combined data analysis. The generic solutions fare quite well when a nonzero curvature parameter ${\ensuremath{\Omega}}_{K}^{(0)}$ is taken into account, but the Akaike and Bayesian information criteria show that they are not particularly favored over the $\ensuremath{\Lambda}\mathrm{CDM}$ model.

Suzaku observation of a1689: anisotropic temperature and entropy distributions associated with the large-scale structure

Abstract: We present results of new, deep Suzaku X-ray observations (160 ks) of the intracluster medium (ICM) in A1689 out to its virial radius, combined with complementary data sets of the projected galaxy distribution obtained from the SDSS catalog and the projected mass distribution from our recent comprehensive weak and strong lensing analysis of Subaru/Suprime-Cam and Hubble Space Telescope/Advanced Camera for Surveys observations. Faint X-ray emission from the ICM around the virial radius (r vir ~ 156) is detected at 4.0σ significance, thanks to the low and stable particle background of Suzaku. The Suzaku observations reveal anisotropic gas temperature and entropy distributions in cluster outskirts of r 500 r r vir correlated with large-scale structure of galaxies in a photometric redshift slice around the cluster. The high temperature (~5.4 keV) and entropy region in the northeastern (NE) outskirts is apparently connected to an overdense filamentary structure of galaxies outside the cluster. The gas temperature and entropy profiles in the NE direction are in good agreement, out to the virial radius, with that expected from a recent XMM-Newton statistical study and with an accretion shock heating model of the ICM, respectively. On the contrary, the other outskirt regions in contact with low-density void environments have low gas temperatures (~1.7 keV) and entropies, deviating from hydrostatic equilibrium. These anisotropic ICM features associated with large-scale structure environments suggest that the thermalization of the ICM occurs faster along overdense filamentary structures than along low-density void regions. We find that the ICM density distribution is fairly isotropic, with a three-dimensional density slope of –2.29 ± 0.18 in the radial range of r 2500 r r 500, and with –1.24+0.23 –0.56 in r 500 r r vir, which, however, is significantly shallower than the Navarro, Frenk, and White universal matter density profile in the outskirts, ρ r –3. A joint X-ray and lensing analysis shows that the hydrostatic mass is lower than the spherical-lensing one (~60%-90%), but comparable to a triaxial halo mass within errors, at intermediate radii of 0.6r 2500 r 0.8r 500. On the other hand, the hydrostatic mass within 0.4r 2500 is significantly biased as low as 60%, irrespective of mass models. The thermal gas pressure within r 500 is, at most, ~50%-60% of the total pressure to balance fully the gravity of the spherical-lensing mass, and ~30%-40% around the virial radius. Although these constitute lower limits when one considers the possible halo triaxiality, these small relative contributions of thermal pressure would require additional sources of pressure, such as bulk and/or turbulent motions.

Identifying Strategies That Facilitate EFL Learners' Oral Communication: A Classroom Study Using Multiple Data Collection Procedures

Abstract: This article considers whether the use of specific communication strategies can improve learners' English proficiency in communicative tasks. Japanese college students ( n = 62) participated in a 12-week course of English lessons using a communicative approach with strategy training. To investigate the influence of specific strategy use, their performance on a posttraining conversation test was analyzed through multiple data collection procedures. Transcripts of the test were made and then analyzed in terms of production rate, the number of errors, and actual strategy use. An Oral Communication Strategy Inventory was introduced to elicit participants' communication strategy use for a self-report questionnaire procedure. These results were compared with participants' retrospective protocol data regarding their oral test performance. The findings confirmed that strategies for maintaining discourse and negotiation of meaning could enhance learners' communicative ability. Yet the students used a relatively small number of examples of modified output, which indicated that they might not have enough opportunities to improve the form of their utterances. [ABSTRACT FROM AUTHOR]

Electrochemical Insertion of Li and Na Ions into Nanocrystalline Fe3O4 and α‐Fe2O3 for Rechargeable Batteries

Abstract: Fe 3 O 4 powders with different particle sizes on average (400, 100, and 10 nm) were prepared and characterized by X-ray diffraction, transmission electron microscopy, Mossbauer spectroscopy, and electrochemical methods. To examine the electrochemical activity of Fe 3 O 4 in relation to the particle size effect, galvanostatic cycling tests in aprotic electrolytes containing lithium or sodium ions were conducted. The electrochemical activity was significantly enhanced as the mean particle size decreased. The nanocrystallized Fe 3 O 4 (10 nm) prepared by precipitation method delivered 190 mA h g ―1 of the rechargeable capacity in the voltage range of 2-3 V in a lithium-ion containing electrolyte, whereas the 400 and 100 nm Fe 3 O 4 powders showed 10 and 80 mA h g ―1 of the rechargeable capacity, respectively. An ex situ X-ray diffraction study for the electrochemically cycled samples suggested the partly reversible Fe ion migration from the tetrahedral sites to the octahedral sites with a retained spinel framework structure. The nanocrystallized Fe 3 O 4 as well as α-Fe 2 O 3 were highly electrochemically active in the sodium salt electrolyte. The rechargeable capacity of 160 or 170 mA h g ―1 with excellent capacity retention was obtained for nanocrystalline Fe 3 O 4 or α-Fe 2 O 3 , respectively.

Dark energy: investigation and modeling

Abstract: Constantly accumulating observational data continue to confirm that about 70% of the energy density today consists of dark energy responsible for the accelerated expansion of the Universe. We present recent observational bounds on dark energy constrained by the type Ia supernovae, cosmic microwave background, and baryon acoustic oscillations. We review a number of theoretical approaches that have been adopted so far to explain the origin of dark energy. This includes the cosmological constant, modified matter models (such as quintessence, k-essence, coupled dark energy, unified models of dark energy and dark matter), modified gravity models (such as f(R) gravity, scalar-tensor theories, braneworlds), and inhomogeneous models. We also discuss observational and experimental constraints on those models and clarify which models are favored or ruled out in current observations.

Superconductivity and Structural Phase Transitions in Caged Compounds RT2Zn20 (R = La, Pr, T = Ru, Ir)

Abstract: Electrical resistivity ρ, specific heat C , magnetization M measurements are reported on four compounds, LaRu 2 Zn 20 , PrRu 2 Zn 20 , LaIr 2 Zn 20 , and PrIr 2 Zn 20 , which crystallize in a cubic CeCr 2 Al 20 -type structure. LaRu 2 Zn 20 , LaIr 2 Zn 20 , and PrIr 2 Zn 20 show superconducting transitions at T C = 0.2, 0.6, and ∼0.05 K, respectively, whereas PrRu 2 Zn 20 remains a normal state down to 0.04 K. This is the first observation of superconductivity in the family of RT 2 X 20 (T = transition metal; X = Al and Zn). Furthermore, structural phase transitions manifest themselves at T s = 150, 138, and 200 K for LaRu 2 Zn 20 , PrRu 2 Zn 20 , and LaIr 2 Zn 20 , respectively. No magnetic transition is found in PrRu 2 Zn 20 and PrIr 2 Zn 20 down to 1.8 K. On cooling PrIr 2 Zn 20 below 2 K, the specific heat divided by temperature, C / T , continuously increases and reaches 5 J/(K 2 ·mol) at 0.4 K, suggesting that Pr 4 f 2 electrons are involved in the heavy-fermion state, as observed in a related compo...

Synthesis of cold antihydrogen in a cusp trap.

Abstract: We report here the first successful synthesis of cold antihydrogen atoms employing a cusp trap, which consists of a superconducting anti-Helmholtz coil and a stack of multiple ring electrodes. This success opens a new path to make a stringent test of the CPT symmetry via high precision microwave spectroscopy of ground-state hyperfine transitions of antihydrogen atoms.

HgII Ion Specifically Binds with T:T Mismatched Base Pair in Duplex DNA

Abstract: Metal-mediated base pair formation, resulting from the interaction between metal ions and artificial bases in oligonucleotides, has been developed for its potential application in nanotechnology. We have recently found that the T:T mismatched base pair binds with Hg(II) ions to generate a novel metal-mediated base pair in duplex DNA. The thermal stability of the duplex with the T-Hg-T base pair was comparable to that of the corresponding T:A or A:T. The novel T-Hg-T base pair involving the natural base thymine is more convenient than the metal-mediated base pairs involving artificial bases due to the lack of time-consuming synthesis. Here, we examine the specificity and thermodynamic properties of the binding between Hg(II) ions and the T:T mismatched base pair. Only the melting temperature of the duplex with T:T and not of the perfectly matched or other mismatched base pairs was found to specifically increase in the presence of Hg(II) ions. Hg(II) specifically bound with the T:T mismatched base pair at a molar ratio of 1:1 with a binding constant of 10(6) M(-1), which is significantly higher than that for nonspecific metal ion-DNA interactions. Furthermore, the higher-order structure of the duplex was not significantly distorted by the Hg(II) ion binding. Our results support the idea that the T-Hg-T base pair could eventually lead to progress in potential applications of metal-mediated base pairs in nanotechnology.