Transition path sampling has been applied to the molecular dynamics of the alanine dipeptide in vacuum and in aqueous solution. The analysis shows that more degrees of freedom than the traditional dihedral angles, phi and psi, are necessary to describe the reaction coordinates for isomerization of this molecule. In vacuum, an additional dihedral angle is identified as significant. In solution, ...

We address here the manner in which acid catalysis senses the strength of solid acids. Acid strengths for Keggin polyoxometalate (POM) clusters and zeolites, chosen because of their accurately known structures, are described rigorously by their deprotonation energies (DPE). Mechanistic interpretations of the measured dynamics of alkane isomerization and alkanol dehydration are used to obtain ra...

Urinary excretion of the type I collagen C-telopeptide (CTx) has been shown to be a sensitive index of the rate of bone resorption. The human type I collagen sequence A(1209)HDGGR(1214) of CTx can undergo racemization of the aspartic acid residue Asp(1211) and isomerization of the bond between this residue and Gly(1212). These spontaneous non-enzymic chemical reactions takes place in vivo in bo...

We demonstrate the application of molecular rotational spectroscopy to measure the conformation isomerization rate of vibrationally excited pent-1-en-4-yne (pentenyne). The rotational spectra of single quantum states of pentenyne are acquired by using a combination of IR-Fourier transform microwave double-resonance spectroscopy and high-resolution, single-photon IR spectroscopy. The quantum sta...

Proline is a unique amino acid owing to the relatively small energy difference between the cis and trans conformations of its peptide bond. The X-Pro imide bond readily undergoes cis-trans isomerization in the context of short peptides as well as some proteins. However, the direct detection of cis-trans proline isomerization in folded proteins is technically challenging. NMR spectroscopy is wel...

In the previous paper, one of the authors described "A Survey on the Dextrose Industry in Japan and its Future" in the 1967 issue. As shown in the earlier paper, the supply and demand situation of starch in this country was drastically changed since 1963-64. In the later 1950's, the Japanese Government had a big problem to eliminate the big stock of the over-produced sweet potato starch. Theref...

Some new 3-(alkylsulfanyl)- 7-chloro-1-phenyl-1H-pyridazino [4,3-e][1,3,4]thiadiazine were synthesized  by treatment of the alkyl-2-phenylhydrazinecarbodithioates with 4-bromo-3,6-dichloropyridazine in alkaline acetonitril. Orientation of the reaction has been determined by X-Ray crystallography technique. The chlorine atom on the number 7 position of these products was replaced by secondary am...

The present work discusses the influence of additives, designated as co-adjuvants agents chemical activation, containing nitrogen on their structure, activated carbons (ACs) produced from waste polyethylene terephthalate (PET) and cork by with KOH, at 973 K. used were urea, 2-chloro-4,6-diamino-1,3,5-triazine, (2-hydroxyethyl) urea polyethylenimine. ACs, PET, only KOH presented a porous volume ...