The 2-aminopyridine2-pyridone (2AP2PY) dimer is linked by N-H...O=C and N-H...N hydrogen bonds, providing a model for the Watson-Crick hydrogen bond configuration of the adenine.thymine and adenine.uracil nucleobase pairs. Mass-specific infrared spectra of 2AP2PY and its seven N-H deuterated isotopomers have been measured between 2550 and 3650 cm(-1) by IR laser depletion combined with UV two-c...

The dissociation of the hydroxymethyl radical, CH(2)OH, and its isotopolog, CD(2)OH, following the excitation of high OH stretch overtones is studied by quasi-classical molecular dynamics calculations using a global potential energy surface (PES) fitted to ab initio calculations. The PES includes CH(2)OH and CH(3)O minima, dissociation products, and all relevant barriers. Its analysis shows tha...

This study was designed to evaluate effects of light-irradiated intensities directly and indirectly through resin composites to one- and two-step self-etch adhesives on dentin bonding. One-step (Clearfil S(3) Bond; TS, Bond Force; BF) or two-step (Clearfil SE Bond; SE) self-etch adhesives was applied to dentin surface. The adhesive agent was light-cured with light-intensity of 350 or 600 mW/cm(...

Regelation, i.e., ice melts under compression and freezes again when the pressure is relieved, remains puzzling since its discovery in 1850's by Faraday. Here we show that hydrogen bond (O:H-O) cooperativity and its extraordinary recoverability resolve this anomaly. The H-O bond and the O:H nonbond possesses each a specific heat ηx(T/ΘDx) whose Debye temperature ΘDx is proportional to its chara...

Puerariae Flos, the flowers of Pueraria. lobata (WILLD.) OHWI, is an important oriental crude drug used to ameliorate crapulence. In the preceding paper,' we described two triterpenoidal glycosides of the sophoradiol glucuronides, along with the known six aromatic compounds, kakkalide, daidzin, genistin, rutin, robinin and nicotiflorin. This paper further deals with a tryptophan derivative, ten...

We present detailed theoretical studies of the H-bonded complexes formed from interaction between 5-fluorouracil and various six-membered cyclic nitrosamine compounds. In this study, an investigation on intermolecular interactions in X-NU (X = CH2, SiH2,BH, AlH, NH, PH, O and S) complexes is carried out using density functional theory. The calculations are conducted on B3L...

It has been found that ultrasonic treatment of diamond nanopowders contributes to surface cleaning due the removal non-diamond carbon and impurities from boundary nanodiamond grains (from 0.4 0.32 % for ASUD-99 0.67 0.55 ASUD 75, respectively). does not affect total sorption volume values specific studied samples do change, but it changes composition groups on nanoparticles, which its hydrophil...