The chemical properties of an element are primarily governed by the configuration of electrons in the valence shell. Relativistic effects influence the electronic structure of heavy elements in the ...sixth row of the periodic table, and these effects increase dramatically in the seventh row--including the actinides--even affecting ground-state configurations. Atomic s and p1/2 orbitals are stabilized by relativistic effects, whereas p3/2, d and f orbitals are destabilized, so that ground-state configurations of heavy elements may differ from those of lighter elements in the same group. The first ionization potential (IP1) is a measure of the energy required to remove one valence electron from a neutral atom, and is an atomic property that reflects the outermost electronic configuration. Precise and accurate experimental determination of IP1 gives information on the binding energy of valence electrons, and also, therefore, on the degree of relativistic stabilization. However, such measurements are hampered by the difficulty in obtaining the heaviest elements on scales of more than one atom at a time. Here we report that the experimentally obtained IP1 of the heaviest actinide, lawrencium (Lr, atomic number 103), is 4.96(+0.08)(-0.07) electronvolts. The IP1 of Lr was measured with (256)Lr (half-life 27 seconds) using an efficient surface ion-source and a radioisotope detection system coupled to a mass separator. The measured IP1 is in excellent agreement with the value of 4.963(15) electronvolts predicted here by state-of-the-art relativistic calculations. The present work provides a reliable benchmark for theoretical calculations and also opens the way for IP1 measurements of superheavy elements (that is, transactinides) on an atom-at-a-time scale.
Fission-fragment mass distributions were measured for ^{237-240}U, ^{239-242}Np, and ^{241-244}Pu populated in the excitation-energy range from 10 to 60 MeV by multinucleon transfer channels in the ...reaction ^{18}O+^{238}U at the Japan Atomic Energy Agency tandem facility. Among them, the data for ^{240}U and ^{240,241,242}Np were observed for the first time. It was found that the mass distributions for all the studied nuclides maintain a double-humped shape up to the highest measured energy in contrast to expectations of predominantly symmetric fission due to the washing out of nuclear shell effects. From a comparison with the dynamical calculation based on the fluctuation-dissipation model, this behavior of the mass distributions was unambiguously attributed to the effect of multichance fission.
Tsukada K, Nishio S, Usami S, and the Deafness Gene Study Consortium. A large cohort study of GJB2 mutations in Japanese hearing loss patients.
GJB2 is the gene most frequently associated with ...hereditary hearing loss, and the GJB2 mutation spectrums vary among different ethnic groups. In this study, the mutation spectrum as well as clinical features of patients with GJB2 mutations as found in more than 1000 Japanese hearing loss families are summarized. The present results show that the frequency of GJB2 mutations in the Japanese population with hearing loss is 14.2% overall and 25.2% in patients with congenital hearing loss. c.235delC was the most frequent allele (49.8%), was associated with a more severe phenotype, and was mainly found in patients who were diagnosed by the age of 3. In contrast, the second most frequent was p.V37I (16.5%), which has a milder phenotype and was mainly found in patients diagnosed at a higher age. Additional clinical features in hearing loss patients with GJB2 mutations in this study were the near absence of tinnitus, vestibular dysfunction and inner ear malformations.
Under the background of extensive improvement of renewable resources and demand for reliable emergency power supply, we proposed a hybrid energy storage system including an electric double-layer ...capacitor bank and a hydrogen system which is composed of fuel cell, electrolyzer, gas tank and metal hydride tank. Through its integration with photovoltaic power sources in a local direct current grid, we expect to obtain both of stable energy source at ordinary times and long-time reliable autonomous emergency power supply when outages happen. A three-day demonstration of the proposed system was performed. The fluctuation compensation performance of the components and the long-time stable power supply obtained by the entire system were evaluated at first, hence the configuration and the management methods of the proposed system were verified in the autonomous emergency power supply application. Meanwhile, the performance of the hybrid use of the gas tank and the metal hydride tank in the system was preliminarily evaluated, for its effectiveness verification on reducing auxiliary power for temperature condition of the metal hydride tank. Moreover, we investigated the distribution characteristics of the power and energy loss in the electric double-layer capacitor, electrolyzer and fuel cell, and their correlation to the efficiency characteristics under different conditions during the operation. The investigation results showed that the continual low-load-ratio state of the electrolyzer and fuel cell led to the low efficiency, the rare high-power occurrence of the electrolyzer and fuel cell led their demanded excessive power capacity. Thus, we proposed a solution method of shifting the electrolyzer and fuel cell's load to the EDLC, when the electrolyzer and fuel cell are in low-load-ratio and excessive high-power state, in order for efficiency increase and facility capacity reduction.
•Proposed a hydrogen storage composed of gas tank and metal hydride tank in series.•Realized 72-hour demonstration of an electric and hydrogen energy storage system.•Verified system's ability of reliable long-time autonomous emergency power supply.•Clarified electrolyzer and fuel cell's low efficiency and excessive capacity issue.•Proposed solution method of load shift from electrolyzer and fuel cell to EDLC.
In order to realize a large-capacity stand-alone emergency power supply that enables highly reliable and high-quality power supply at the time of a large-scale natural disaster and enables effective ...use of solar power generation, we proposed an electric and hydrogen hybrid energy storage system (HESS). It is composed of an electric double-layer capacitor bank, fuel cell, electrolyzer, and hydrogen storage (buffer gas tank and metal hydride). In an emergency, this HESS is expected to supply power for loads together with photovoltaics panels for a long time. In usual time, it should not only cooperate with external electricity grids to convert unstable photovoltaic output power into reliable power supply, but also maintain sufficient stored energy in case of emergency. To realize the continuous operation of the HESS in both emergency and usual time, we proposed an electric double-layer capacitor's state-of-charge feedback control method and a hydrogen energy feedback control method, coordinating an energy management method based on Kalman filter algorithm. An experiment and a simulation demonstrated the operations of a 10-kW scale model HESS in emergency and usual time mode, respectively. The demonstrations verified the correct performance of the proposed HESS with the proposed control methods and enabled the continuous operation of the HESS.
•Developed energy control methods in an electric and hydrogen energy storage system.•Enabled long-time continuous operation of the system by the energy control methods.•Verified system’s operation as stand-alone emergency power supply by an experiment.•Verified the operation for effective on-grid PV power generation by a simulation.
Background. Little information is available on the incidence of renal stones with ritonavir-boosted atazanavir (ATV/r) use. Methods. In a single-center study, the incidence of renal stones was ...compared between human immunodeficiency virus (HIV)—infected patients who commenced ritonavir-boosted atazanavir (ATV/r)—containing antiretroviral (ARV) therapy (the ATV/r group) and those who were receiving other protease inhibitors (the other PIs group). The effects of ATV/r were estimated by univariate and multivariate Cox proportional hazards regression models. Other possible risk factors were evaluated by univariate analysis, and those found to be significant were entered into multivariate analysis. Results. Renal stones were diagnosed in 31 patients (23.7 cases per 1000 person-years) in the ATV/r group (n = 465) and 4 in patients (2.2 cases per 1000 person-years) in the other PIs group (n = 775). ATV/r use was significantly associated with renal stones, by univariate and multivariate analyses (adjusted hazard ratio, 10.44; 95% confidence interval CI, 3.685–29.59; P < .001). ATV/r remained a significant risk factor for renal stones in all subgroups stratified by the median values of baseline variables. In the 31 patients receiving ATV/r who developed renal stones, the median time from commencement of ATV/r to diagnosis was 24.5 months (interquartile range, 14.7–34.6 months). Of the 18 patients who continued ATV/r despite the diagnosis of renal stones, 6 (33.3%) experienced recurrence. No patient who discontinued ATV/r experienced recurrence during the observation period (250.6 person-months). Conclusions. The incidence of renal stones was substantially higher among patients in the ATV/r group, compared with patients in the other PIs group. Continuation of ATV/r after diagnosis of renal stones was associated with a high rate of recurrence. Switching ATV/r to other ARVs is warranted in patients who develop renal stones.
Experimental investigations of transactinoide elements provide benchmark results for chemical theory and probe the predictive power of trends in the periodic table. So far, in gas-phase chemical ...reactions, simple inorganic compounds with the transactinoide in its highest oxidation state have been synthesized. Single-atom production rates, short half-lives, and harsh experimental conditions limited the number of experimentally accessible compounds. We applied a gas-phase carbonylation technique previously tested on short-lived molybdenum (Mo) and tungsten (W) isotopes to the preparation of a carbonyl complex of seaborgium, the 106th element. The volatile seaborgium complex showed the same volatility and reactivity with a silicon dioxide surface as those of the hexacarbonyl complexes of the lighter homologs Mo and W. Comparison of the product’s adsorption enthalpy with theoretical predictions and data for the lighter congeners supported a Sg(CO)₆ formulation.
Mammary tumors that spontaneously occurred in domestic Djungarian hamsters (Phodopus sungorus) were histologically examined. Forty-five mammary tumors included 14 adenomas, 18 adenocarcinomas, 1 ...lipid-rich carcinoma, 2 adenoacanthomas, 2 malignant adenomyoepitheliomas, 1 benign mixed tumor, and 7 “balloon cell” carcinosarcomas. The latter 4 types were newly recognized neoplasms in Djungarian hamsters. The relatively high incidence of spontaneous mammary carcinosarcomas in domestic Djungarian hamsters is intriguing. Carcinosarcomas exhibited anomalous histological features made up of a mixture of glandular cells, polygonal cells (including “balloon cells”), and sarcomatous spindle cells in varying proportions. Transitional features from glandular cells to polygonal cells and subsequently to sarcomatous spindle cells were observed. Using immunohistochemistry, we observed that glandular cells exhibited an epithelial phenotype (cytokeratin(+)/vimentin(–)), spindle cells exhibited a mesenchymal phenotype (cytokeratin(–)/vimentin(+)), and polygonal cells exhibited an intermediate phenotype (cytokeratin(+)/vimentin(+)). Reduction or loss of β-catenin expression and gain of S100A4 expression were observed in polygonal and spindle cells. The polygonal cell population included a varying number of characteristic cells that were expanded by large intracytoplasmic vacuoles. Electron microscopy revealed that these “balloon cells” had large cytoplasmic lumens lined by microvilli. These observations suggest that epithelial-mesenchymal transition may account for the pathogenesis of mammary carcinosarcomas in Djungarian hamsters.
Our group has developed a coil using MgB2 wires for SMES. In this paper, a prototype coil using a MgB2 Rutherford-type stranded conductor was fabricated based on react-and-wind (R&W) method. In the ...R&W method, a Rutherford-type conductor in which nine MgB2 wires were wound at pitch of 450 mm around a copper former were manufactured using reacted wires (performed by Columbus Superconductors SpA), and then coiling was performed. The coil was cooled by conduction cooling and the I-V properties were evaluated under magnetic field. As a result, in the R&W method, critical current of a coil was degraded, since making a coil by hand would cause the strain beyond the scope of the assumption which was the marginally allowable bending strain. This result suggests the coil for SMES proposed in ASPCS is difficult to react before twisting, and Rutherford-type conductors should be fabricated before reacting, which means that coil processing should be performed based on the React after making stranded conductors and Wind method, or the wind-and-react method.
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