Trilinear Lp estimates with applications to the Cauchy problem for the Hartree-type equation

In this paper, $L^p$ estimates for a trilinear operator associated with the Hartree type nonlinearity are proved. Moreover, as application of these estimates, it is proved that after a linear transformation, the Cauchy problem for the Hartree-type equation becomes locally well posed in the Bessel potential and homogeneous Besov spaces under certain regularity assumptions on the initial data. This notion of well-posedness and the functional framework to solve the equation were firstly proposed by Y. Zhou.     

Stable meso‐Aryl β‐Alkyl Hybrid Sapphyrin with a Warped π‐Conjugation Circuit and Neo‐Confused Sapphyrin–Silver(I) Complex

A meso‐aryl and β‐alkyl substituted sapphyrin and its rhodium(I) and silver complexes were synthesized. This sapphyrin was so stable that the non‐inverted and warped structure could be analyzed by X‐ray crystallography even in its neutral state. Its bis‐rhodium(I) complex has a more planar structure than the sapphyrin with enhanced aromaticity over the conjugation circuit. On the other hand, silver metalation of the sapphyrin caused a marked core rearrangement into a neo‐confused sapphyrin derivative with a C(α)?N bond and a twisted macrocycle.     

A mass spectrometric study of the decomposition of trymethylarsine (TMAs) with triethylgallium (TEGa)

The decomposition mechanisms of trimethylarsine (TMAs) with triethylgallium (TEGa) were studied using a sampling gas method with a mass spectrometer. When TEGa is present, the TMAs concentration starts to decrease at temperatures about 100°C lower than for TMAs alone. The TMAs concentration in the gas phase decreases simultaneously with TEGa decomposition. The rate constant of the TMAs concentration decrease is strongly affected by the TMAs/TEGa mole ratio. However, the TEGa decomposition rate is not affected by the TMAs/TEGa mole ratio. The TMAs concentration decrease is mostly due to the decomposition of the adduct between TMAs and TEGa. TMAs in the gas phase starts to decompose and generate methane at 400°C. However, some TMAs molecules probably adsorb on the reactor surface and/or are incorporated into the GaAs crystal as carbon. Between 340 and 450°C, the concentration of carbon in the TMAs adsorbed on the surface as TMAs and/or incorporated into GaAs as carbon atom is stable and keeps a constant concentration: the TMAs generates no methane.     

EXAFS measurements for liquid As2Se3 at high temperatures and pressures

Extended X-ray absorption fine structure (EXAFS) spectra from liquid As₂Se₃ around both the As and Se K-edges in the temperature-pressure range up to 1400°C and about 60 bar were measured. For the EXAFS measurements, a new type of high pressure vessel and a sample cell of own design made of polycrystalline sapphire were developed. Distinct EXAFS oscillations were obtained even at 1400°C. When the semiconductor-to-metal transition occurs at about 1000°C, the local environment around a central As atoms is substantially changes and a new As neighbor site is induced.     

Determination of boron in water samples at nanograms per cubic decimeter levels by reversed-phase partition high-performance liquid chromatography with precolumn complexation reaction using salicylaldehyde and 1-amino-8-naphthol-3,6-disulfonate

A new method for the highly sensitive and selective determination of boron at nanograms per cubic decimeter levels has been developed based on the derivatization reaction of boron using salicylaldehyde and 1-amino-8-naphtol-3,6-disulfonate with reversed-phase partition high-performance liquid chromatography. A detection limit as low as 2.0 nmol/dm³ (22 ng/dm³) was achieved without any preconcentration. No significant interference was observed in the determination of 16 μmol/dm³ of boron with the addition of nine metal ions (Al^III, Cu^II, Co^II, Fe^II, Fe^III, Ni^II, Mn^II, V^V, Zn^II) at concentrations 100 times greater than that of boron without any masking procedure. The proposed method was successfully applied to the determination of boron in river water, tap water, doubly distilled water, and highly purified water. Figure Scheme of formation of boron-azomethine-H complex with salicylaldehyde and 1-amino-8-naphthol-3, 6-disulfonate     

Photoluminescent properties and molecular structures of [NaphAu(PPh(3))] and [mu-Naph {Au(PPh(3))}(2)] ClO(4) (Naph = 2-naphthyl)

The complexes [NaphAu(PPh(3))], and [mu-Naph{Au(PPh(3))}(2)]ClO(4), having the Au-C (aromatic) bond have been synthesized and characterized. The unique structure of with two gold atoms bridged by a naphthyl group has been determined by X-ray crystallography. The intramolecular Au-Au separation in is 2.7731(4) A. Upon excitation at 266 nm, both complexes display intraligand phosphorescence at room temperature in solution and in solid state.     

Ab initio protein structure prediction with force field parameters derived from water-phase quantum chemical calculation

Molecular dynamics (MD) simulations are extensively used in the study of the structures and functions of proteins. Ab initio protein structure prediction is one of the most important subjects in computational biology, and many trials have been performed using MD simulation so far. Since the results of MD simulations largely depend on the force field, reliable force field parameters are indispensable for the success of MD simulation. In this work, we have modified atom charges in a standard force field on the basis of water-phase quantum chemical calculations. The modified force field turned out appropriate for ab initio protein structure prediction by the MD simulation with the generalized Born method. Detailed analysis was performed in terms of the conformational stability of amino acid residues, the stability of secondary structure of proteins, and the accuracy for prediction of protein tertiary structure, comparing the modified force field with a standard one. The energy balance between alpha-helix and beta-sheet structures was significantly improved by the modification of charge parameters.     

Force field parameters for rotation around chi torsion axis in nucleic acids

To raise the accuracy of the force field for nucleic acids, several parameters were elaborated, focusing on the rotation around chi torsion axis. The reliability of molecular dynamics (MD) simulation was significantly increased by improving the torsion parameters at C8--N9--C1'--X (X = H1', C2', O4') in A, G and those at C6--N1--C1'--X in C, T, and U. In this work, we constructed small models representing the chemical structure of A, G, C, T, and U, and estimated energy profile for chi-axis rotation by executing numerous quantum mechanical (QM) calculations. The parameters were derived by discrete Fourier transformation of the calculated QM data. A comparison in energy profile between molecular mechanical (MM) calculation and QM one shows that our presently derived parameters well reproduce the energy surface of QM calculation for all the above torsion terms. Furthermore, our parameters show a good performance in MD simulations of some nucleic acids. Hence, the present refinement of parameters will enable us to perform more accurate simulations for various types of nucleic acids.