This organic laboratory experiment introduces students to stereoselective enzyme reactions, resolution of enantiomers, and NMR analysis of diastereomers. The reaction between racemic 1-phenylethanol and vinyl acetate in hexane to form an ester is catalyzed by acylase I. The unreacted alcohol is then treated with a chiral acid and the resulting ester diastereomer is analyzed by NMR. This experim...

The molecular deformation of cotton cellulose whisker/epoxy resin (CW/EP) and tunicate whisker/poly(vinyl) acetate (TW/PVAc) composites were investigated using Raman spectroscopy. A shift in the 1095 cm Raman peak position is recorded for samples deformed in both tension and compression, which corresponds to the molecular deformation of the cellulose chains within the whiskers. Cyclic molecular...

Disinfection was investigated in high-density ozone produced by dielectric barrier discharge under atmospheric pressure. Disinfection was studied on three-dimensional carriers made of hydrophilic vinyl-polysiloxane impression material and granular acrylic resin used for oral surgery. Experimental results indicate disinfection of spore-forming bacteria: Geobacillus stearothermophilus and Bacillu...

Initiator integrated 3D printing, namely i3DP, was developed by incorporating a vinyl-terminated initiator into UV curable resin to make functional structural materials that enable genetic post-printing surface-initiated modification. Taking advantage of 3D printing and surface-initiated ATRP, the feasible i3DP makes 3D printed complex architectures possible for nearly any desired surface modif...

Intermolecular radical 1,2-addition (IRA) of N-tert-butyl-N-(1-diethylphosphono-2,2-dimethylpropyl)aminoxyl (SG1) based alkoxyamines onto activated olefins is used as a tool for peptide ligation. This strategy relies on simple peptide pre-derivatization to obtain (i) a SG1 nitroxide functionalized resin peptide at its N-terminus (SG1-peptide alkoxyamine), (ii) a vinyl functionalized peptide (ei...

Chemical structures of photocured acrylic ester resins were characterized using specific decomposition techniques such as pyrolysis-gas chromatography in the presence of organic alkali and matrixassisted laser desorption/ionization mass spectrometry combined with super critical methanolysis. The resultant products formed through specific cleavage at the ester linkages in the cured resin samples...

2-Cyclopenten-1-one-5-carboxylic ester derivatives 14 are synthesized in a four-step-reaction sequence starting from alkynyl aldehydes 9 via 4Z-b-vinyl-a-diazo b-ketoesters intermediate 8. The synthetic method for 8 is described. When the d substituent is an alkyl group, Rh(II)-mediated decomposition of the diazo compounds 8 led to an intramolecular C–H insertion to afford 2-cyclopenten-1-one-5...

Fourier transform (FT-) Raman spectroscopy excited with a 1064 nm laser can be used to determine the content of plasticizers in commercial flexible poly vinyl chloride (PVC) products. Our previous study [T. Nørbygaard, R.W. Berg, Analysis of phthalate ester content in PVC plastics by means of FT-Raman Spectroscopy, Appl. Spectrosc. 58 (4) (2004) 410–413]—on detection of the presence of phthalat...

The aim of this study was to evaluate the influence of different resin cements on the cuspal deflection of endodontically treated teeth restored with composite resin inlays. Sixty upper premolars were randomly divided into five groups (n=12): 1 - sound teeth; 2 - cavity; 3 - Rely X ARC; 4 - RelyX Unicem; 5 - SeT. The teeth from groups 2, 3, 4 and 5 received a MOD preparation and endodontic trea...