An inhibitory compound against the interaction between G alpha(s) and the third intracellular loop region of serotonin receptor subtype 6 (5-HT6) disrupts the signaling pathway of 5-HT6

Serotonin receptor subtype 6 (5-HT(6)) is a neurotransmitter receptor, which is involved in various brain functions such as memory and mood. It mediates signaling via the interaction with a stimulatory G-protein. Especially, the third intracellular loop (iL3) of 5-HT(6) and the alpha subunit of stimulatory G protein (G alpha(s)) are responsible for the signaling process of 5-HT(6). Chemical compounds that could inhibit the interaction between the iL3 region of 5-HT(6) and G alpha(s) were screened from a chemical library consisted of 5,600 synthetic compounds. One of the identified compounds bound to G alpha(s) and effectively blocked the interaction between G alpha(s) and the iL3 region of 5-HT(6). The identified compound was further shown to reduce the serotonin-induced accumulation of cAMP in 293T cells transformed with 5-HT(6) cDNA. It also lowered the Ca(2+) efflux induced by serotonin in cells expressing 5-HT(6) and chimeric G alpha(s5/q). These results indicate that the interaction between the iL3 of 5-HT(6) and G alpha(s) can be exploited for screening of regulatory compounds against the signaling pathway of 5-HT(6).     

Dianthiamides A–E,Proline-Containing Orbitides from Dianthus chinensis

Orbitides are plant-derived small cyclic peptides with a wide range of biological activities. Phytochemical investigation of the whole plants of Dianthus chinensis was performed with the aim to discover new bioactive orbitides. Five undescribed proline-containing orbitides, dianthiamides A–E (1–5), were isolated from a methanolic extract of Dianthus chinensis. Their structures were elucidated by extensive analysis of 1D and 2D NMR and HRESI–TOF–MS as well as ESI–MS/MS fragmentation data. The absolute configuration of the amino acid residues of compounds 1–5 was determined by Marfey’s method. All compounds were tested for their cytotoxic activity, and dianthiamide A (1) exhibited weak activity against A549 cell line with IC₅₀ value of 47.9 μM.     

Do the generalized Fock-state wave functions have some relations with classical initial condition?

We examine whether the general type Fock-state wave functions for the harmonic oscillator have some relations with the classical initial condition.     

Quantum Mechanical Algorithm for Solving Quadratic Residue Equation

We propose a quantum mechanical algorithm for solving quadratic residue equation z ²=b (mod M) based on Grover quantum search. The quantum algorithm will take O( ?M\sqrt{M} ) steps for finding the solutions to the equation by exploiting the properties of quantum superposition and interference effect, while classical algorithm to the same problem will take O(M) steps. The success probability of the algorithm approaches to unity and the cost of the algorithm mainly depends on the calculations of quadratic residue modulo M and the number of iterations. Furthermore, we show that the algorithm can be used to solve the prime factorization problem, and the computing complexity is O( ?N\sqrt{N} ).     

Enhanced electrical conductivity of Ag-mercaptosuccinic acid-redoped polyaniline nanoparticles during thermal cycling above 200 °C

Ag-doped polyaniline (PANI) nanoparticles are prepared via doping-dedoping-redoping with the thiol group in mercaptosuccinic acid (MSA) providing the linkage between PANI molecules and Ag atoms. Ag-MSA-doped PANI maintains the electrical conductivity well above the room-temperature value of 3.0 S/cm up to 220 °C, reaching its maximum (9.0 S/cm) at 180 °C. In addition, Ag-MSA-doped PANI nanoparticles show remarkable stability against repeated thermal aging at 120 °C. The room-temperature conductivity, in fact, increases by a factor of ∼3 after 3 cycles of thermal aging. The enhanced stability against repeated thermal aging is attributed to the formation of uniformly distributed Ag nanoparticles within the PANI particles upon heating.     

Effect of the urethane group on treated clay surfaces for high-performance poly(butylene succinate)/montmorillonite nanocomposites

We successfully modified organic clays containing the urethane group by introducing a covalent bond between the silanol group on the clay side and the hydroxyl group of organic modifier in the silicate layer using 1,6-diisocyanatohexane (HDI), namely surface-treated montmorillonite (30BM), to increase both basal spacing and the favorable interaction between clay and polymer. The effect of the surface urethane modification of clay on poly (butylene succinate) (PBS)/30BM nanocomposites was studied. The results of transmission electron microscopy micrographs at a 10-nm resolution and X-ray diffraction measurements allowed us to examine the degree of the high exfoliation and the effect of surface urethane modification on clay dispersibility. As results of high exfoliation, PBS/30BM nanocomposites not only exhibited the high thermal properties, but also showed a remarkable increase in physical properties (e.g., tensile strength, Young's modulus, elongation at break) due to enhanced affinity between the clay and PBS matrix. Over all, the results suggest that wide gallery spacing and the predominant affinity between PBS and clay must be considered simultaneously to increase the degree of exfoliation and physical properties as key factors.     

Structures and Magnetic Properties of Two Copper(II) Complexes with 2,5‐Dichloro‐3,6‐Dihydroxy‐1,4‐Benzoquinone Dianionic and Tetrachloroquinone Ligand

The polynuclear copper(II) complex [Cu₂(Hdpa)₂(μ‐ClDHBQ)(ClO₄)₂]_n, 1 is bridged by ClDHBQ^?2 (2,5‐dichloro‐3,6‐dihydroxy‐1,4‐benzoquinone dianionic) and 2,2′‐dipyridylamine (Hdpa). In the axial position, Cu is connected with the oxygen atom of ClO. The perchlorate anion may be envisaged as a monodentate O‐bound ligand. Through the bond bridge of O–Cu … O–Cl, the binuclear compound [Cu₂(Hdpa)₂(μ‐ClDHBQ)(ClO₄)₂] is strung together into a long chain compound. Tetrachlorocatechol underwent partial oxidation/hydrolysis/dechlorination processes to produce ClDHBQ^?2. The other mononuclear complex [Cu(Hdpa)(TeCQ)](DMF), 2 , in which tetrachloroquinone (TeCQ) was produced by oxidation of tetrachlorocatechol (TeCC), therefore complex 2 is in the quinone form. The magnetic susceptibility measurements show antiferromagnetic coupling with J = ?11.9 cm^?1, θ = 2.6 K, and g = 2.05 for complex 1. Complex 2 exhibits the typical paramagnetic behavior of s = 1/2.