The Effect of Substituent on Molecules That Contain a Triple Bond Between Arsenic and Group 13 Elements: Theoretical Designs and Characterizations

The effect of substitution on the potential energy surfaces of RE13≡AsR (E13 = group 13 elements; R = F, OH, H, CH3, and SiH3) is determined using density functional theory (M06‐2X/Def2‐TZVP, B3PW91/Def2‐TZVP, and B3LYP/LANL2DZ+dp). The computational studies demonstrate that all triply bonded RE13≡AsR species prefer to adopt a bent geometry that is consistent with the valence electron model. The theoretical studies also demonstrate that RE13≡AsR molecules with smaller substituents are kinetically unstable, with respect to the intramolecular rearrangements. However, triply bonded R′E13≡AsR′ species with bulkier substituents (R′ = SiMe(SitBu3)2, SiiPrDis2, and NHC) are found to occupy the lowest minimum on the singlet potential energy surface, and they are both kinetically and thermodynamically stable. That is to say, the electronic and steric effects of bulky substituents play an important role in making molecules that feature an E13≡As triple bond as viable synthetic target

Magnetic and gravity interpretation of Yaloc-69 data from the Cocos plate area

Magnetic, gravity and bathymetry data were collected on an extended cruise of the R/V Yaquina in 1969. The last set of data was obtained from those track lines leaving the Panama Basin. The area covered is mainly the Cocos plate (Molnar and Sykes, 1969). The data is analyzed and compared with results of previous workers and the geophysical implications considered. Generally speaking, from the magnetic part of the data, both direct and indirect methods show support of Vine and Matthew's (1963) hypothesis of sea-floor spreading and the subsequent principles of new global tectonics. The most northern magnetic anomaly profile across the East Pacific rise (at 18.3°N) shows a spreading rate about 3 cm/yr. and the most southern one (at 12.8°N) shows a rate about 5.2 cm/yr. The Cocos plate has been assumed to move in a northeast-southwest direction (N30°E to N45°E), and rotate with respect to the Pacific plate about a pole at 40°N, 110°W with an angular velocity of 19.6x10⁻⁷ deg./yr. (Larson and Chase, 1970). New material comes up from the west boundary - the East Pacific rise, and the south boundary - the Galapogos rift, causing the Cocos plate to underthrust the Americans plate at the middle American arc. Some of the points of new global tectonics can not be detected from this set of data; further detailed study of more track lines and sea bottom core samples are needed. The results of both analytical methods for determining the magnitude of induced and remanent magnetization in the second layer shows some consistence with the work of Schaeffer and Schwarz (1970), and Irving et al. (1970) at the Mid-Atlantic ridge near 45°N, in which a thinner magnetization layer at the ridge and the attenuation of magnetization intensity away from the ridge axis are suggested. Free-air gravity anomaly profiles have been employed to determine the crustal structure of two sections1 a ridge section at 12.8°N and a trench section at 14°N. For the ridge section, if the anomalous mantle was converted from normal mantle, the extension of anomalous mantle into the normal mantle requires some uplift and/or lateral expansion in the rise crest area. The tensional configuration suggested in the trench crustal section agrees with the model proposed by Elsasser (1968) for the differential movement between two lithospheric blocks. This work gives some speculations that evidence which supports the present new global tectonics theory is limited to a certain degree of accuracy. Further study of the theory based upon physics, its mechanism, and measurement techniques that would give more reliable evidence have to be developed before it can be ascertained what really happens beneath this wild, wild world

Tailoring excitonic states of van der Waals bilayers through stacking configuration, band alignment and valley-spin

Excitons in monolayer semiconductors have large optical transition dipole for strong coupling with light field. Interlayer excitons in heterobilayers, with layer separation of electron and hole components, feature large electric dipole that enables strong coupling with electric field and exciton-exciton interaction, at the cost that the optical dipole is substantially quenched (by several orders of magnitude). In this letter, we demonstrate the ability to create a new class of excitons in transition metal dichalcogenide (TMD) hetero- and homo-bilayers that combines the advantages of monolayer- and interlayer-excitons, i.e. featuring both large optical dipole and large electric dipole. These excitons consist of an electron that is well confined in an individual layer, and a hole that is well extended in both layers, realized here through the carrier-species specific layer-hybridization controlled through the interplay of rotational, translational, band offset, and valley-spin degrees of freedom. We observe different species of such layer-hybridized valley excitons in different heterobilayer and homobilayer systems, which can be utilized for realizing strongly interacting excitonic/polaritonic gases, as well as optical quantum coherent controls of bidirectional interlayer carrier transfer either with upper conversion or down conversion in energy

Triple Bonds between Bismuth and Group 13 Elements: Theoretical Designs and Characterization

The effect of substitution on the potential energy surfaces of RE13≡BiR (E13 = B, Al, Ga, In, and Tl; R = F, OH, H, CH3, SiH3, Tbt, Ar*, SiMe(SitBu3)2, and SiiPrDis2) is investigated using density functional theories (M06-2X/Def2-TZVP, B3PW91/Def2-TZVP, and B3LYP/LANL2DZ+dp). The theoretical results suggest that all of the triply bonded RE13≡BiR molecules prefer to adopt a bent geometry (i.e., ∠RE13Bi ≈ 180° and ∠E13BiR ≈ 90°), which agrees well with the bonding model (model (B)). It is also demonstrated that the smaller groups, such as R = F, OH, H, CH3, and SiH3, neither kinetically nor thermodynamically stabilize the triply bonded RE13≡BiR compounds, except for the case of H3SiB≡BiSiH3. Nevertheless, the triply bonded RʹE13≡BiRʹ molecules that feature bulkier substituents (Rʹ = Tbt, Ar*, SiMe(SitBu3)2, and SiiPrDis2) are found to have the global minimum on the singlet potential energy surface and are both kinetically and thermodynamically stable. In other words, both the electronic and the steric effects of bulkier substituent groups play an important role in making triply bonded RE13≡BiR (Group 13–Group 15) species synthetically accessible and isolable in a stable form

Decadal Oscillation of Fall Temperature in Taiwan

This study verifies the existence of an evident decadal oscillation in fall (September - November) temperature for Taiwan. It has an island-wide spatial pattern and a central frequency of 11 years. Acorresponding decadal-oscillation mode of tropical sea surface temperature (SST) is found to be largely responsible for inducing the decadal temperature oscillation for Taiwan via the following regulating processes. On a decadal timescale, periods of decadal warming in Taiwan concur with major cold anomalies in tropical SST over the eastern Indian Ocean and the central Pacific. These cold SST anomalies modulate tropical Walker circulation so as to produce anomalous descending centers in their regions. Meanwhile, the complementary anomalous ascending motion and anomalous low-level convergence center occur near the Maritime continent. These anomalous ascending and descending centers act as tropical forcing sources to evoke a low-level Rossby-wave-like circulation anomaly in the Asian-Pacific regions. Taiwan is surrounded by a low-level anomalous high to its east and an anomalous low to its west. These circulations induce anomalous flows from the south to warm Taiwan via anomalous warm advection. The above regulating processes reverse in polarity during periods of decadal cooling in Taiwan

Epigallocatechin-3-gallate-mediated cardioprotection by Akt/GSK-3β/caveolin signalling in H9c2 rat cardiomyoblasts

Background: Epigallocatechin-3-gallate (EGCg) with its potent anti-oxidative capabilities is known for its beneficialeffects ameliorating oxidative injury to cardiac cells. Although studies have provided convincing evidence tosupport the cardioprotective effects of EGCg, it remains unclear whether EGCg affect trans-membrane signalling incardiac cells. Here, we have demonstrated the potential mechanism for cardioprotection of EGCg againstH2O2-induced oxidative stress in H9c2 cardiomyoblasts.Results: Exposing H9c2 cells to H2O2 suppressed cell viability and altered the expression of adherens and gapjunction proteins with increased levels of intracellular reactive oxygen species and cytosolic Ca2+. These detrimentaleffects were attenuated by pre-treating cells with EGCg for 30 min. EGCg also attenuated H2O2-mediated cell cyclearrest at the G1-S phase through the glycogen synthase kinase-3β (GSK-3β)/β-catenin/cyclin D1 signalling pathway.To determine how EGCg targets H9c2 cells, enhanced green fluorescence protein (EGFP) was ectopically expressedin these cells. EGFP-emission fluorescence spectroscopy revealed that EGCg induced dose-dependent fluorescencechanges in EGFP expressing cells, suggesting that EGCg signalling events might trigger proximity changes of EGFPexpressed in these cells.Proteomics studies showed that EGFP formed complexes with the 67 kD laminin receptor, caveolin-1 and -3,β-actin, myosin 9, vimentin in EGFP expressing cells. Using in vitro oxidative stress and in vivo myocardial ischemiamodels, we also demonstrated the involvement of caveolin in EGCg-mediated cardioprotection. In addition,EGCg-mediated caveolin-1 activation was found to be modulated by Akt/GSK-3β signalling in H2O2-induced H9c2cell injury.Conclusions: Our data suggest that caveolin serves as a membrane raft that may help mediate cardioprotectiveEGCg transmembrane signalling