Temperature-sensitive reaction intermediate of F1-ATPase

F1-ATPase is a rotary molecular motor that makes 120° stepping rotations, with each step being driven by a single-ATP hydrolysis. In this study, a new reaction intermediate of F1-ATPase was discovered at a temperature below 4°C, which makes a pause at the same angle in its rotation as when ATP binds. The rate constant of the intermediate reaction was strongly dependent on temperature with a Q10 factor of 19, implying that the intermediate reaction accompanies a large conformational change. Kinetic analyses showed that the intermediate state does not correspond to ATP binding or hydrolysis. The addition of ADP to the reaction mixture did not alter the angular position of the intermediate state, but specifically lengthened the time constant of this state. Conversely, the addition of inorganic phosphate caused a pause at an angle of +80° from that of the intermediate state. These observations strongly suggest that the newly found reaction intermediate is an ADP-releasing step

Multiparametric analysis for pharynx SCC

Purpose : To predict local control / failure by a multiparametric approach using magnetic resonance (MR)-derived tumor morphological and functional parameters in pharynx squamous cell carcinoma (SCC) patients. Materials and Methods : Twenty-eight patients with oropharyngeal and hypopharyngeal SCCs were included in this study. Quantitative morphological parameters and intratumoral characteristics on T2-weighted images, tumor blood flow from pseudo-continuous arterial spin labeling, and tumor diffusion parameters of three diffusion models from multi-b-value diffusion-weighted imaging as well as patients’ characteristics were analyzed. The patients were divided into local control / failure groups. Univariate and multiparametric analysis were performed for the patient group division. Results : The value of morphological parameter of ‘sphericity’ and intratumoral characteristic of ‘homogeneity’ was revealed respectively significant for the prediction of the local control status in univariate analysis. Higher diagnostic performance was obtained with the sensitivity of 0.8, specificity of 0.75, positive predictive value of 0.89, negative predictive value of 0.6 and accuracy of 0.79 by multiparametric diagnostic model compared to results in the univariate analysis. Conclusion : A multiparametric analysis with MR-derived quantitative parameters may be useful to predict local control in pharynx SCC patients

Signature of hidden order and evidence for periodicity modification in URu₂Si₂

The detail of electronic structures near the Fermi level in URu2Si2 has been investigated employing state-of-art laser angle-resolved photoemission spectroscopy. The observation of a narrow dispersive band near the Fermi level in the ordered state as well as its absence in a Rh-substituted sample strongly suggest that the emergence of the narrow band is a clear signature of the hidden-order transition. The temperature dependence of the narrow band, which appears at the onset of the hidden-order transition, invokes the occurrence of periodicity modification in the ordered state, which is shown for the first time by any spectroscopic probe. We compare our data to other previous studies and discuss possible implications

Electronic Structure of the Novel Filled Skutterudite PrPt₄Ge₁₂ Superconductor

We have performed soft x-ray photoemission spectroscopy (SXPES) and resonant photoemission spectroscopy (RPES) of the filled skutterudite superconductor PrPt4Ge12 in order to study the electronic structure of valence band and the character of Pr 4f. SXPES of PrPt4Ge12 measured with 1200 eV photon energy, where spectral contribution of Pr 4f is negligible, was found nearly identical with that of LaPt4Ge12, indicating similarity of Pt–Ge derived electronic states of the two compounds. Good correspondence with band calculations allows us to ascribe the dominant Ge 4p character of the density of states at the Fermi level (EF). Pr 3d → 4f RPES shows that, although Pr 4f electrons in PrPt4Ge12 are not as strongly hybridized with conduction electrons near EF as in PrFe4P12, there are finite Pr 4f contribution to the states near EF in PrPt4Ge12. These PES results give the information of fundamental electronic structure for understanding the physical properties of the novel filled skutterudite superconductor PrPt4Ge12

Analysis on photoemission spectrum of superconducting FeSe

In this paper, we present the result of soft X-ray photoemission spectroscopy and its comparison with the density functional calculation. Although local density approximation seems to be a good starting point for describing the electronic structure of FeSe, the simulated spectrum poorly reproduced the structure around E(B) = 2 eV. This result suggests the necessity of theoretical treatment beyond local density approximation

Multiple phosphorus chemical sites in heavily phosphorus-doped diamond

We have performed high-resolution core level photoemission spectroscopy on a heavily phosphorus (P)-doped diamond film in order to elucidate the chemical sites of doped-phosphorus atoms in diamond. P 2p core level study shows two bulk components, providing spectroscopic evidence for multiple chemical sites of doped-phosphorus atoms. This indicates that only a part of doped-phosphorus atoms contribute to the formation of carriers. From a comparison with band calculations, possible origins for the chemical sites are discussed

Ultrahigh-resolution laser photoemission study of URu₂Si₂ across the hidden-order transition

We have studied the electronic structures of URu2Si2 employing ultrahigh-resolutionlaser angle-resolved photoemission spectroscopy. The change of photoemission spectra is investigated across the hidden-ordertransition, and the emergence of a narrow band is clearly observed near the Fermi level for both (π,0) and (π,π) directions. In addition, it is shown that tuning of light's polarization allows the signal of a hole-like dispersive feature to enhance. These observations prove that laser angle-resolved photoemission spectroscopy is an effective tool for studying the evolution of electronic structures across the hidden-ordertransition in URu2Si2