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  • Barbour Clayton posted an update 4 days, 6 hours ago

    A novel metal-free, efficient cascade reaction has been developed to construct 1,2,3-triazole-fused 1,4-diazepinone skeletons. Mechanism investigation indicated that sodium azide has not only served as a 1,3-dipoles synthon in [3 + 2] cycloaddition but also prompted C-N bond formation. Furthermore, the potential utility of this protocol was demonstrated by scale-up synthesis of 1,2,3-triazole-fused diazepinone derivatives and the derivatization of them.As one of the most promising nonfullerene acceptors for organic photovoltaics, perylene diimide (PDI)-based multibranched molecules with twisted or three-dimensional (3D) geometric structures have been developed, which effectively increase the power conversion efficiency (PCE) of organic solar cells. Understanding the structure-property relationships in multichromophoric molecular architectures at molecular and ultrafast time levels is a crucial step in establishing new design principles in organic electronic materials. For this, photodriven excited-state symmetry-breaking charge separation (SB-CS) of PDI-based multichromophoric acceptors has been proposed to improve the PCE by reducing the self-aggregation of the planar PDI monomer. Herein, we investigated the intramolecular excited-state SB-CS and charge recombination (CR) dynamics of two symmetric phenyl-methane-based PDI derivatives, a twist dimer PM-PDI2 (phenyl-methane-based PDI dimer) and a 3D configuration tetramer PM-PDI4 (phenyl-methane-based PDI te PDI units in PM-PDI4. Besides, the 3D structure of PM-PDI4 also restricts rotation to a surface crossing region between the excited state and ground state, thus inhibiting nonradiative CR process and increasing the CS state lifetime. Our results suggest that the kinetics of CS and CR processes are strongly related to the molecular geometric structure, and the excited-state symmetry breaking in the 3D structure acceptor has superior photogenerated charge and photovoltaic properties from the perspective of ultrafast dynamics.Our work reveals a class of three-dimensional materials whose main features are dominated by d-orbital states. Their unique properties are derived from the low-energy states t2g. Without spin-orbital coupling (SOC), we find a triple degenerate point with a quadratic dispersion, demonstrated by an effective Hamiltonian. When SOC is included, the sign of SOC could determine the topological phases of materials a negative SOC contributes a Dirac semimetal phase with a quadratic energy dispersion, whereas a positive SOC leads to a strong topological insulator phase. There exist clear surface states for the corresponding topological phases. Very interestingly, by application of a triaxial strain, the sequence of bands can be exchanged, as do the topological phases. In particular, there exists a 6-fold degenerate point under a critical strain. Furthermore, we use a uniaxial compressive/tensile strain, changing the quadratic Dirac point into a linear Dirac/strong topological insulator phase.Drimys brasiliensis (Winteraceae) has been investigated in traditional medicine for its anti-inflammatory properties to treat gastric ulcers and allergic and respiratory system diseases as well as for cancer treatment. buy Bay 11-7085 In this work, we investigate the ability of the sesquiterpene polygodial, isolated from D. brasiliensis stem barks, to modulate the chronic inflammatory response induced by polyester-polyurethane sponge implants in C57BL/6J mice. Daily treatment with polygodial inhibited the macrophage content in the implants as determined by the activity of the N-acetyl-β-d-glucosaminidase enzyme as well as decreased the levels of CXCL1/KC and CCL2/JE/MCP-1 pro-inflammatory chemokines and the presence of mast cells along the formed fibrovascular tissue. Similarly, the deposition of a new extracellular matrix (total collagen and type I and III collagen fibers) as well as the production of the TGF-β1 cytokine were attenuated in implants treated with polygodial, showing for the first time its antifibrogenic capacity. The hemoglobin content, the number of newly formed vessels, and the levels of VEGF cytokine, which were used as parameters for the assessment of the neovascularization of the implants, did not change after treatment with polygodial. The anti-inflammatory and antifibrogenic effects of polygodial over the components of the granulation tissue induced by the sponge implant indicate a therapeutic potential for the treatment of inflammatory diseases associated with the development of fibrovascular tissue.The performance of the isotropic spherical atom model can be significantly enhanced through combination with anisotropic three-body dispersion interactions to give the new PFD-3B density functional, which reduces the mean absolute deviation (MAD) relative to CCSD(T)/CBS benchmark energies from 0.78 to 0.19 kcal/mol for the S22 test set. Comparison with the extended S22 × 5 test set in the figure indicates that this accuracy is maintained through large variations in geometry. The performance of the PFD-3B functional over the S22 × 5 test set is superior to any of the functionals previously applied to this set. Over the S22 set of examples, the MADs from the CCSD(T)/CBS values for Re, De, and ωe, are 0.032 Å, 0.21 kcal/mol, and 6 cm-1, respectively. Over a comparable set of 26 examples containing second and third row atoms, the MADs from the CCSD(T)/CBS values for Re, De, and ωe, are 0.033 Å, 0.19 kcal/mol, and 5 cm-1, respectively. If used to optimize the geometry of the 48 examples, on average the PFD-3B functional introduces an error of only 0.042 kcal/mol in CCSD(T) single-point energies. This small error combines with the reported analytical first and second derivatives to makes the PFD-3B functional an attractive model for geometry optimization and zero-point energy calculations.Since some antifreeze proteins and glycoproteins (AF(G)Ps) cannot directly bind to all ice crystal planes, they change ice crystal morphology by minimizing the area of the crystal planes to which they cannot bind until crystal growth is halted. Previous studies found that growth along the c-axis (perpendicular to the basal plane, the crystal plane to which these AF(G)Ps cannot bind) is accelerated by some AF(G)Ps, while growth of other planes is inhibited. The effects of this growth acceleration on crystal morphology and on the thermal hysteresis activity are unknown to date. Understanding these effects will elucidate the mechanism of ice growth inhibition by AF(G)Ps. Using cold stages and an infrared laser, ice growth velocities and crystal morphologies in AF(G)P solutions were measured. Three types of effects on growth velocity were found concentration-dependent acceleration, concentration-independent acceleration, and concentration-dependent deceleration. Quantitative crystal morphology measurements in AF(G)P solutions demonstrated that the adsorption rate of the proteins to ice plays a major role in determining the morphology of the bipyramidal crystal.