C-type lectin Mincle-dependent and -independent activation of invariant NKT cells by exposure to Helicobacter pylori α-cholesteryl glucosides.

Helicobacter pylori extracts cholesterol from the host and converts it to its glycosides. We found that cholesteryl 6'-O-acyl α-glucoside (ChAcαG) produced by H. pylori is recognised by both invariant Vα14 NKT (iNKT) cells and a C-type lectin receptor Mincle (Clec4e).

Control of Fe coordination by excess Cl in alcohol solutions.

We spectroscopically investigated coordination state of Fe in methanol (MeOH) and ethanol (EtOH) solutions against Cl concentration ([Cl]). In both the system, we observed characteristic absorption bands due to the FeCl complex at high-[Cl] region. In the MeOH system, the proportion () of [FeCl] exhibits a stationary value of 0.

Synchrotron X-ray Electron Density Analysis of Chemical Bonding in the Graphitic Carbon Nitride Precursor Melamine.

Melamine is a precursor and building block for graphitic carbon nitride (g-CN) materials, a group of layered materials showing great promise for catalytic applications. The synthetic pathway to g-CN includes a polycondensation reaction of melamine by evaporation of ammonia. Melamine molecules in the crystal organize into wave-like planes with an interlayer distance of 3.

Delayed Onset and Directionality of X-Ray-Induced Atomic Displacements Observed on Subatomic Length Scales.

Transient structural changes of Al_{2}O_{3} on subatomic length scales following irradiation with an intense x-ray laser pulse (photon energy: 8.70 keV; pulse duration: 6 fs; fluence: 8×10^{2}  J/cm^{2}) have been investigated by using an x-ray pump x-ray probe technique. The measurement reveals that aluminum and oxygen atoms remain in their original positions by ∼20  fs after the intensity maximum of the pump pulse, followed by directional atomic displacements at the fixed unit cell parameters.

Multicomponent Crystals with Competing Intermolecular Interactions: In Situ X-ray Diffraction and Luminescent Features Reveal Multimolecular Assembly under Mechanochemical Conditions.

Supramolecular chemistry under mechanochemical conditions has drawn attention because it can induce low-solubility molecules to self-assemble, although most of the reported examples have been limited to two-component systems. We applied mechanochemical synthesis to achieve multimolecular self-assembly in more challenging three-component systems. The produced crystals showed multicolor solid-state luminescence depending on the components when exposed to UV light.

Quantum-Enhanced Heat Engine Based on Superabsorption.

We propose a quantum-enhanced heat engine with entanglement. The key feature of our scheme is superabsorption, which facilitates enhanced energy absorption by entangled qubits. Whereas a conventional engine with N separable qubits provides power with a scaling of P=Θ(N), our engine uses superabsorption to provide power with a quantum scaling of P=Θ(N^{2}).

Dynamic ionic radius of alkali metal ions in aqueous solution: a pulsed-field gradient NMR study.

The dynamic behavior of alkali metal ions, Li, Na, K, Rb and Cs in aqueous solutions is one of the most important topics in solution chemistry. Since these alkali metals contain nuclear magnetic resonance (NMR) active nuclei, it is possible to directly measure the diffusion constants of the alkali metal ions using the pulsed field gradient (PFG) NMR method. In this paper, the Li, Na, Rb, Cs and H resonances are observed for diffusion constants in aqueous solution and the solvent HO.

Structure Factors and Charge Density Description of Aluminum: A Quantum Crystallographic Study.

Static structure factors and charge density for metallic aluminum were investigated by periodic calculations using atom-centered Gaussian-type basis sets with the Perdew-Burke-Ernzerhof (PBE) functional implemented in the CRYSTAL14 package and X-ray constrained wave function (XCW) fitting. The effects of additional diffuse d and f basis functions on structure factors were compared with synchrotron powder X-ray diffraction and quantitative convergent electron beam diffraction data. Changes in structure factors from an independent atom model at 022, 113, and 222 reflections introduced d and f basis functions similar to those of the experimental data.

X-ray Electron Density Study of the Chemical Bonding Origin of Glass Formation in Metal-Organic Frameworks.

Glass-forming metal-organic frameworks (MOFs) have novel applications, but the origin of their peculiar melting behavior is unclear. Here, we report synchrotron X-ray diffraction electron densities of two zeolitic imidazolate frameworks (ZIFs), the glass-forming Zn-ZIF-zni and the isostructural thermally decomposing Co-ZIF-zni. Electron density analysis shows that the Zn-N bonds are more ionic than the Co-N bonds, which have distinct covalent features.

Enhancement of the mechanical and thermal transport properties of carbon nanotube yarns by boundary structure modulation.

Carbon nanotubes (CNTs) exhibit extremely high nanoscopic thermal/electrical transport and mechanical properties. However, the macroscopic properties of assembled CNTs are significantly lower than those of CNTs because of the boundary structure between the CNTs. Therefore, it is crucial to understand the relationship between the nanoscopic boundary structure in CNTs and the macroscopic properties of the assembled CNTs.

Enantioselective reaction of -cyano imines: decarboxylative Mannich-type reaction with malonic acid half thioesters.

The enantioselective reaction of imines bearing a cyano group as an activating group with malonic acid half thioesters gave chiral cyanamide derivatives with high enantioselectivity. The density functional theory (DFT) calculation clarified the stereochemical outcome and importance of the -cyano group for imines.

Facile Multiple Alkylations of C Fullerene.

The reduction of fullerene (C) with sodium dispersion in the presence of an excess amount of dipropyl sulfate was found to yield highly propylated fullerene, C(CH) (max. = 24), and C(CH) was predominantly generated as determined by mass spectroscopy.

Recovery of Au from dilute aqua regia solutions via adsorption on the lyophilized cells of a unicellular red alga Galdieria sulphuraria: A mechanism study.

The high electrical conductivity, chemical stability, and low toxicity of elemental Au make it a highly valuable resource. However, wastewater produced during the mining, utilization, and disposal of Au inevitably contains small amounts (10-40 mg L) of Au, thus posing environmental risks. It is too acidic to be treated with inexpensive and eco-friendly bioadsorbents previously studied for the remediation of less acidic effluents.

Direct observation of one-dimensional disordered diffusion channel in a chain-like thermoelectric with ultralow thermal conductivity.

Structural disorder, highly effective in reducing thermal conductivity, is important in technological applications such as thermal barrier coatings and thermoelectrics. In particular, interstitial, disordered, diffusive atoms are common in complex crystal structures with ultralow thermal conductivity, but are rarely found in simple crystalline solids. Combining single-crystal synchrotron X-ray diffraction, the maximum entropy method, diffuse scattering, and theoretical calculations, here we report the direct observation of one-dimensional disordered In chains in a simple chain-like thermoelectric InTe, which contains a significant In vacancy along with interstitial indium sites.

Electron transfer phase transition and oxidization process in NaCoMn[Fe(CN)] (0.00 ≤ ≤ 1.60).

We investigated the phase diagram of NaCoMn[Fe(CN)] in the entire Na concentration range of 0.00 ≤ ≤ 1.60.

Fabrication of Hydrogen Boride Thin Film by Ion Exchange in MgB.

In this study, hydrogen boride films are fabricated by ion-exchange treatment on magnesium diboride (MgB) films under ambient temperature and pressure. We prepared oriented MgB films on strontium titanate (SrTiO) substrates using pulsed laser deposition (PLD). Subsequently, these films were treated with ion exchangers in acetonitrile solution.

Polymer Optical Microcavity Sensor for Volatile Organic Compounds with Distinct Selectivity toward Aromatic Hydrocarbons.

A whispering-gallery mode (WGM) optical resonance sensor for volatile organic compounds (VOCs) is developed from polystyrene (PS) microspheres doped with fluorescent β-cyano-appended oligo(-phenylenevinylene) (β-COPV). The β-COPV-doped PS microspheres (MS) are formed by the miniemulsion method in a binary solvent. MS expand upon permeation of VOCs into the PS matrix and exhibit a spectral shift of the WGM resonance peak.

Solvophobicity-directed assembly of microporous molecular crystals.

Dense packing is a universal tendency of organic molecules in the solid state. Typical porous crystals utilize reticular strong intermolecular bonding networks to overcome this principle. Here, we report a solvophobicity-based methodology for assembling discrete molecules into a porous form and succeed in synthesizing isostructural porous polymorphs of an amphiphilic aromatic molecule PyMes.

Direct Visualization of Nearly Free Electron States Formed by Superatom Molecular Orbitals in a Li@C Monolayer.

Using scanning tunneling microscopy (STM) and density functional theory (DFT) calculations, we directly determine the spatial and energetic distributions of superatom molecular orbitals (SAMOs) of an Li@C monolayer adsorbed on a Cu(111) surface. Utilizing a weakly bonded [Li@C] NTf (NTf: bis(trifluoromethanesulfonyl)imide) salt makes it possible to produce a Li@C monolayer with high concentration of Li@C molecules. Because of the very uniform adsorption geometry of Li@C on Cu(111), the p-SAMO, populated the upper hemisphere of the molecule, exhibits an isotropic and delocalized nature, with an energy that is significantly lower compared to that of C.

Evidence of C-F···H-C Attractive Interaction: Enforced Coplanarity of a Tetrafluorophenylene-Ethynylene-Linked Porphyrin Dimer.

The formation of C-F···H-C "hydrogen bonds" has been a controversial subject because, in principle, fluorine is hardly an acceptor for less acidic protons contrasting to the C-F···H-O and C-F···H-N hydrogen bonds. Nevertheless, the interaction is emerging as a powerful implement for confining the torsional rotation in the design of fully coplanar π-conjugated polymers. Heretofore, no evidence of the C-F···H-C interaction has been observed in solutions.

A cationic copolymer as a cocatalyst for a peroxidase-mimicking heme-DNAzyme.

Heme binds to a parallel-stranded G-quadruplex DNA to form a peroxidase-mimicking heme-DNAzyme. An interpolyelectrolyte complex between the heme-DNAzyme and a cationic copolymer possessing protonated amino groups was characterized and the peroxidase activity of the complex was evaluated to elucidate the effect of the polymer on the catalytic activity of the heme-DNAzyme. We found that the catalytic activity of the heme-DNAzyme is enhanced through the formation of the interpolyelectrolyte complex due to the general acid catalysis of protonated amino groups of the polymer, enhancing the formation of the iron(IV)oxo porphyrin π-cation radical intermediate known as Compound I.

The advanced treatment of hydrogen bonding in quantum crystallography.

Although hydrogen bonding is one of the most important motifs in chemistry and biology, H-atom parameters are especially problematic to refine against X-ray diffraction data. New developments in quantum crystallography offer a remedy. This article reports how hydrogen bonds are treated in three different quantum-crystallographic methods: Hirshfeld atom refinement (HAR), HAR coupled to extremely localized molecular orbitals and X-ray wavefunction refinement.

Solvent-dependent /-isomerization and self-assembly of triply helical complexes bearing a pivot part.

Tris-chelate metal complexes of unsymmetrical bidentate ligands can form two geometric stereoisomers, () and () isomers. Due to the small difference in their properties, the highly-selective synthesis of one of the isomers is challenging. We now designed a series of tripodal ligands with a tris(3-(2-(methyleneoxy)ethoxy)phenyl)methane pivot.

Synthesis of Pyrrole-Based Poly(arylenevinylene)s via Co-Catalyzed Hydroarylation of Alkynes.

Polyaddition via the Co-catalyzed hydroarylation of 1-(2-pyrimidinyl)pyrrole with aromatic diynes affords poly(arylenevinylene)s under mild conditions. This reaction avoids production of stoichiometric amounts of by-products. Although structural analysis of the obtained polymers reveals the presence of 1,1-vinylidene unit, switching the counter anion of the Co catalyst and steric hindrance of the diyne monomers improves the regioselectivity of the polymers.