Mechanistic Insights into Rhenium-Catalyzed Regioselective C-Alkenylation of Phenols with Internal Alkynes

A (μ-aryloxo)rhenium complex was isolated and confirmed as a key precatalyst for rhenium-catalyzed ortho-alkenylation (C-alkenylation) of unprotected phenols with alkynes. The reaction exclusively provided ortho-alkenylphenols; the formation of para or multiply alkenylated phenols and hydrophenoxylation (O-alkenylation) products was not observed. Several mechanistic experiments excluded a classical Friedel-Crafts-type mechanism, leading to the proposed phenolic hydroxyl group assisted electrophilic alkenylation as the most plausible reaction mechanism. For this purpose, the use of rhenium, a metal between the early and late transition metals in the periodic table, was key for the activation of both the soft carbon-carbon triple bond of the alkyne and the hard oxygen atom of the phenol, at the same time. ortho-Selective alkenylation with allenes also provided the corresponding adducts with a substitution pattern different from that obtained by the addition reaction with alkynes

Rhenium-Catalyzed Regioselective ortho-Alkenylation and [3 + 2 + 1] Cycloaddition of Phenols with Internal Alkynes

An operationally simple and direct rhenium-catalyzed ortho-alkenylation (C-alkenylation) of unprotected phenols with alkynes was developed. The protocol provided ortho-alkenylphenols exclusively, and formation of para- or multiply alkenylated phenols and hydrophenoxylation (O-alkenylation) products were not observed. The [3 + 2 + 1] cycloaddition of phenols and two alkynes via ortho-alkenylation was also demonstrated, in which the alkynes functioned as both two- and one-carbon units. These reactions proceeded with readily available starting materials under neutral conditions without additional ligands

Design of nucleic acid sequences for DNA computing based on a thermodynamic approach

We have developed an algorithm for designing multiple sequences of nucleic acids that have a uniform melting temperature between the sequence and its complement and that do not hybridize non-specifically with each other based on the minimum free energy (ΔG(min)). Sequences that satisfy these constraints can be utilized in computations, various engineering applications such as microarrays, and nano-fabrications. Our algorithm is a random generate-and-test algorithm: it generates a candidate sequence randomly and tests whether the sequence satisfies the constraints. The novelty of our algorithm is that the filtering method uses a greedy search to calculate ΔG(min). This effectively excludes inappropriate sequences before ΔG(min) is calculated, thereby reducing computation time drastically when compared with an algorithm without the filtering. Experimental results in silico showed the superiority of the greedy search over the traditional approach based on the hamming distance. In addition, experimental results in vitro demonstrated that the experimental free energy (ΔG(exp)) of 126 sequences correlated well with ΔG(min) (|R| = 0.90) than with the hamming distance (|R| = 0.80). These results validate the rationality of a thermodynamic approach. We implemented our algorithm in a graphic user interface-based program written in Java

Gas Sensing Properties of Rutile-tio2 (100) Films Prepared by Pulsed Laser Deposition

Gas sensing property of TiO2 thin films have been demonstrated in rutile-TiO2 (100) films grown on the a-Al2O3 (0001)substrates by Pulsed Laser Deposition (PLD). High quality rutile-TiO2 (100) films were successfully grown on a-Al2O3(0001) with the substrate temperature at 500oC under 15 mTorr of O2 gas pressure. The thickness and crystallinity ofTiO2 films were evaluated by Rutherford backscattering spectrometry combined with channeling (RBS/C) and X-raydiffraction using q-2q scans. To evaluate CO2 gas sensing property of TiO2 films, the dependence of the changing ofelectrical resistivity on the temperature was measured. It's found that high crystallinity rutile-TiO2 (100) films on the a-Al2O3 (0001) substrate kept at 100oC exhibits good gas sensing property for CO2 gas

Collective Excitations and Nonequilibrium Phase Transition in Dissipative Fermionic Superfluids

We predict a new mechanism to induce collective excitations of a fermionic superfluid via sudden switch-on of two-body loss, for which we extend the BCS theory to fully incorporate quantum jumps. We find that such dissipation induces an amplitude oscillation of the superfluid order parameter accompanied by chirped phase rotation, which highlights the role of dissipation in a superfluid as a consequence of particle loss. We demonstrate that when the dissipation is introduced to one of the two superfluids coupled via a Josephson junction, it gives rise to a relative-phase mode analogous to the Leggett mode, which can be detected from time evolution of the Josephson current. We find that the coupled system exhibits a nonequilibrium dissipative phase transition characterized by the vanishing dc Josephson current. The dissipation-induced collective modes can be realized with ultracold fermionic atoms undergoing inelastic collisions.Comment: 13 pages, 7 figure

Construction and reliability of the Japanese version of the Adolescent Egocentrism-Sociocentrism (AES) scale and its preliminary application in the Japanese university students

In recent years, the problem of interpersonal relationships has been reported to be associated with various adolescent psychiatric problems. Egocentrism is one factor related to the problem of interpersonal relationships. The Adolescent Egocentrism- Sociocentrism (AES) scale is used to assess egocentrism in Western countries, but no such scale has been developed in Japan. The purpose of our current study was to develop the Japanese version of the AES scale and investigate the relationship between the egocentrism assessed by the AES scale and the self -consciousness assessed by the Japanese version of the self -consciousness scale. The original version of the AES scale was first translated into Japanese using the forwardbackward method and examined for factorial reliability and validity. The results demonstrated that the Japanese version of the AES scale shows adequate factorial reliability and validity, but different from the original version the “egocentrism personal fable” subscale which measures the feeling that oneself is special and unique was not extracted in the Japanese version. We found a moderate correlation between the non- social focuses of the AES scale and the public self -consciousness subscale of the self –consciousness scale. This correlation suggests that a strong attention of others’ view on oneself results in the avoidance of others. The Japanese version of the AES scale can examine egocentrism adequately together with sociocentrism and non- social focuses. As this scale is self -reporting and easy to complete, it may have practical utility in a clinical setting

A nitrogen isoscape of phytoplankton in the western North Pacific created with a marine nitrogen isotope model

The nitrogen isotopic composition (δ15N) of phytoplankton varies substantially in the ocean reflecting biogeochemical processes such as N2 fixation, denitrification, and nitrate assimilation by phytoplankton. The δ15N values of zooplankton or fish inherit the values of the phytoplankton on which they feed. Combining δ15N values of marine organisms with a map of δ15N values (i.e., a nitrogen isoscape) of phytoplankton can reveal the habitat of marine organisms. Remarkable progress has been made in reconstructing time-series of δ15N values of migratory fish from various tissues, such as otoliths, fish scales, vertebrae, and eye lenses. However, there are no accurate nitrogen isoscapes of phytoplankton due to observational heterogeneity, preventing improvement in the accuracy of estimating migratory routes using the fish δ15N values. Here we present a nitrogen isoscape of phytoplankton in the western North Pacific created with a nitrogen isotope model. The simulated phytoplankton is relatively depleted in 15N at the subtropical site (annual average δ15N value of phytoplankton of 0.6‰), where N2 fixation occurs, and at the subarctic site (2.1‰), where nitrate assimilation by phytoplankton is low due to iron limitation. The simulated phytoplankton is enriched in 15N at the Kuroshio–Oyashio transition site (3.9‰), where nitrate utilization is high, and in the region around the Bering Strait site (6.7‰), where partial nitrification and benthic denitrification occur. The simulated δ15N distributions of nitrate, phytoplankton, and particulate organic nitrogen are consistent with δ15N observations in the western North Pacific. The seamless nitrogen isoscapes created in this study can be used to improve our understanding of the habitat of marine organisms or fish migration in the western North Pacific