Phase and amplitude of Aharonov-Bohm oscillations in nonlinear three-terminal transport through a double quantum dot

We study three-terminal linear and nonlinear transport through an Aharonov-Bohm interferometer containing a double quantum dot using the nonequilibrium Green's function method. Under the condition that one of the three terminals is a voltage probe, we show that the linear conductance is symmetric with respect to the magnetic field (phase symmetry). However, in the nonlinear transport regime, the phase symmetry is broken. Unlike two-terminal transport, the phase symmetry is broken even in noninteracting electron systems. Based on the lowest-order nonlinear conductance coefficient with respect to the source-drain bias voltage, we discuss the direction in which the phase shifts with the magnetic field. When the higher harmonic components of the Aharonov-Bohm oscillations are negligible, the phaseshift is a monotonically increasing function with respect to the source-drain bias voltage. To observe the Aharonov-Bohm oscillations with higher visibility, we need strong coupling between the quantum dots and the voltage probe. However, this leads to dephasing since the voltage probe acts as a B\"{u}ttiker dephasing probe. The interplay between such antithetic concepts provides a peak in the visibility of the Aharonov-Bohm oscillations when the coupling between the quantum dots and the voltage probe changes.Comment: 17 pages, 9 figures, accepted for publication in Physical Review

Pd-catalysed, Ag-assisted C2-H alkenylation of benzophospholes

A palladium-catalysed, silver-assisted regioselective C2-H alkenylation of benzophospholes with terminal alkenes has been developed. The palladium catalysis accommodates styrenes and electron-deficient alkenes including ester, ketone, nitrile, and phosphonate. Thus, this protocol enables the rapid construction of various benzophosphole-vinylene conjugations from the two simple C-H starting substrates. Optical properties of newly synthesized C2-alkenylated benzophospholes are also investigated.Tokura Y., Xu S., Kojima Y., et al. Pd-catalysed, Ag-assisted C2-H alkenylation of benzophospholes. Chemical Communications 58, 12208 (2022); https://doi.org/10.1039/D2CC04942B

Up-conversion glass-ceramic devices of individual emission of red, green and blue and their applications

ABSTRACT When rare earth-doped oxyfluoride glasses are heat-treated at the first crystallization temperatures, the glasses turn into glass-ceramics in which rare earth-containing nanocrystals uniformly precipitate in the glass matrices. These glass-ceramics are transparent to the naked eye as well no heat-treated glasses. Since rare earth ions exist as solidsolution ions in the precipitated fluoride crystals with low phonon energies, these glass-ceramics exhibit highly efficient up-conversion luminescence by laser light excitation. In the present work, rare earth-doped oxyfluoride glass-ceramics in the Si02-PbF2-ErF3-TmF3-GdF3, Si02-PbF2-HoF3-YbF3-GdF3, and Si02-PbF2-TmF3-YbF3-GdF3 systems were developed. Under 980nm LD excitation the respective glass-ceramics gave selectively red-, green-, and blue-upconversion luminescence with high efficiency. Emission wavelengths in the center of gravity are 666, 543,and 479 nm, respectively. Except for these selective emissions, however, other emissions at different wavelengths are also observed, though extremely weak. Removal of these extra emissions was possible by using appropriate filter-glasses, presenting the up-conversion devices of individual emission of red (R), green (G), and blue (B). On the other hand, laminas of the mixtures of resin and the glass-ceramic powders exhibited extremely high enhancement of upconversion emission intensities. The developed upconversion glass-ceramics in which RGB emissions are independently available by 980 nm laser irradiation offer a variety of applications. Some of the expected utilization as optics devices is proposed

Molecular beam epitaxy of superconducting FeSex_{x}Te1−x_{1-x} thin films interfaced with magnetic topological insulators

Engineering heterostructures with various types of quantum materials can provide an intriguing playground for studying exotic physics induced by proximity effect. Here, we report the successful synthesis of iron-based superconductor FeSe$_{x}$Te$_{1-x}$ (FST) thin films in the entire composition of $0 \leq x \leq 1$ and its heterostructure with a magnetic topological insulator by using molecular beam epitaxy. Superconductivity is observed in the FST films with an optimal superconducting transition temperature $T_c$ $\sim$ 12 K at around x = 0.1. We found that superconductivity survives in the very Te-rich films ($x \leq 0.05$), showing stark contrast to bulk crystals with suppression of superconductivity due to an appearance of bicollinear antiferromagnetism accompanied by monoclinic structural transition. By examining thickness t dependence on electrical transport properties, we observed strong suppression of the structural transition in films below t $\sim$ 100 nm, suggesting that substrate effects may stabilize superconducting phase near the interface. Furthermore, we fabricated all chalcogenide-based heterointerface between FST and magnetic topological insulator (Cr,Bi,Sb)$_{2}$Te$_{3}$ for the first time, observing both superconductivity and large anomalous Hall conductivity. The anomalous Hall conductivity increases with decreasing temperature, approaching to the quantized value of $e^2/h$ down to the measurable minimum temperature at $T_c$. The result suggests coexistence of magnetic and superconducting gaps at low temperatures opening at the top and bottom surfaces, respectively. Our novel magnetic topological insulator/superconductor heterostructure could be an ideal platform to explore chiral Majorana edge mode

Population changes in Pythium spp. infecting sanionia moss at the Japanese Ny-Ålesund Observatory, Spitsbergen Island, Norway from 2003 to 2010

第2回極域科学シンポジウム/第33回極域生物シンポジウム 11月18日（金） 統計数理研究所 3階リフレッシュフロ

Low HER2 expression is a predictor of poor prognosis in stage I triple-negative breast cancer

IntroductionTriple-negative breast cancer (TNBC) is negative for hormone receptors and human epidermal growth factor receptor 2 (HER2). In stage I TNBC, adjuvant therapy or follow-up are performed according to risk factors, but clinical trial data is scarce. In recent years, it has been reported that HER2-low cases (1+/2+ and in situ hybridization negative) have different prognoses than HER2-0 cases. However, the risk of recurrence and risk factors in this HER2-low population for stage I TNBC have not yet been investigated.MethodsHerein, out of 174 patients with TNBC who underwent surgery from June 2004 to December 2009 at the National Cancer Center Hospital (Tokyo), we retrospectively examined 42 cases diagnosed as T1N0M0 TNBC after excluding those treated with preoperative chemotherapy.ResultsAll patients were female, the median age was 60.5 years, and 11 cases were HER2-low and 31 cases were HER2-0. The median follow-up period was 121 months. Postoperative adjuvant therapy was administered in 30 patients and recurrence occurred in 8 patients. HER2-low cases showed a significantly shorter disease-free survival (HR: 7.0; 95% CI: 1.2– 40.2; P=0.0016) and a trend towards shorter overall survival (hazard ratio [HR]: 4.2, 95% confidence interval [CI]: 0.58–31.4) compared with that of HER2-0 cases. HER2 was also identified as a factor for poor prognosis from the point- estimated values in univariate and multivariate analyses after confirming that there was no correlation between the other factors.ConclusionFor patients with stage I TNBC, the HER2-low population had a significantly worse prognosis than the HER2-0 population

Pd-catalysed, Ag-assisted C2-H alkenylation of benzophospholes

Tokura Y., Xu S., Kojima Y., et al. Pd-catalysed, Ag-assisted C2-H alkenylation of benzophospholes. Chemical Communications 58, 12208 (2022); https://doi.org/10.1039/D2CC04942B .A palladium-catalysed, silver-assisted regioselective C2-H alkenylation of benzophospholes with terminal alkenes has been developed. The palladium catalysis accommodates styrenes and electron-deficient alkenes including ester, ketone, nitrile, and phosphonate. Thus, this protocol enables the rapid construction of various benzophosphole-vinylene conjugations from the two simple C-H starting substrates. Optical properties of newly synthesized C2-alkenylated benzophospholes are also investigated

Silver Ion Polyelectrolyte Container as a Sensitive Quartz Crystal Microbalance Gas Detector

A polyelectrolyte film containing metastable silver ions was applied as a quartz crystal microbalance (QCM) gas detector. The polyelectrolyte film was obtained by immersing a polyelectrolyte with numerous amine groups in a metal ion solution. The QCM detector with silver ions responded to a very low methylmercaptan gas concentration (20 ppb) but did not respond to ammonia, volatile amines, aromatic compounds, or alcohols. The response speed of the QCM detector increased gradually with increasing methylmercaptan concentrations. The highly sensitive and selective response is promoted by a ligand substitution reaction caused by the formation of coordinative bonds between a metastable silver ion and amine groups in the polyelectrolyte film. To the best of our knowledge, this system has the highest sensitivity among reported QCM gas detectors. Such high-sensitivity among reported QCM gas detectors. Such high-sensitivity gas detectors for volatile sulfur compounds have wide ranging applications in areas such as volcanic eruption prediction, food inspection, environmental analysis, and medical diagnostics