1.Stability of initiation systems in acidic photopolymerizable dental material.
Meereis CT1, Leal FB1, Ogliari FA2. Dent Mater. 2016 Apr 7. pii: S0109-5641(16)30010-0. doi: 10.1016/j.dental.2016.03.016. [Epub ahead of print]
OBJECTIVES: This study simulated the shelf life to evaluate the stability of initiation systems on acidic photopolymerizable dental material, through an experimental self-adhering flowable composite resin (SACR).
2.Immobilization of pectinase on silica-based supports: Impacts of particle size and spacer arm on the activity.
Alagöz D1, Tükel SS2, Yildirim D3. Int J Biol Macromol. 2016 Jun;87:426-32. doi: 10.1016/j.ijbiomac.2016.03.007. Epub 2016 Mar 8.
The pectinase was separately immobilized onto Florisil and nano silica supports through both glutaraldehyde and 3-glyoxypropyltrietoxysilane spacer arms. The effects of spacer arm, particle size of support and ionic liquids on the activities of pectinase preparations were investigated. The immobilization of pectinase onto Florisil and nano silica through 3-glyoxypropyltrietoxysilane spacer arm completely led to inactivation of enzyme; however, 10 and 75% pectinase activity were retained when it was immobilized through glutaraldehyde spacer arm onto Florisil and nano silica, respectively. The pectinase immobilized onto nano silica through glutaraldehyde spacer arm showed 6.3-fold higher catalytic efficiency than that of the pectinase immobilized onto Florisil through same spacer arm. A 2.3-fold increase in thermal stability of pectinase was provided upon immobilization onto nano silica at 35°C. The effects of IL/buffer mixture and volume ratio of IL/buffer mixture on the catalytic activities of free and immobilized pectinase preparations were also tested.
3.Ultrasound-assisted temperature-controlled ionic liquid emulsification microextraction coupled with capillary electrophoresis for the determination of parabens in personal care products.
Ma T1, Li Z1, Jia Q1, Zhou W1. Electrophoresis. 2016 Mar 18. doi: 10.1002/elps.201500533. [Epub ahead of print]
We developed a capillary electrophoresis (CE) and ultrasound-assisted temperature-controlled ionic liquid emulsification microextraction (USA-TC-ILEME) method for the determination of four parabens (methyl paraben, ethyl paraben, propyl paraben and butyl paraben) in personal care products including mouthwash and toning lotion. In the proposed extraction procedure, ionic liquid (1-octyl-3-methylimidazolium hexafluorophosphate) was used as extraction solvent, moreover, no disperser solvent was needed. Parameters affecting the extraction efficiency including volume of ionic liquid, heating temperature, ultrasonic time, extraction time, sample pH, ionic strength and centrifugation time were optimized. Under the optimized conditions, the method was found to be linear over the range of 3-500 ng mL-1 with coefficient of determination (R2 ) in the range of 0.9990-0.9998. The limits of detection and limits of quantification for the four parabens were 0.
4.Diindenopyrenes: Extended 1,6- and 1,8-Pyrenoquinodimethanes with Singlet Diradical Characters.
Hibi D1, Kitabayashi K1, Fujita K1, Takeda T1, Tobe Y1. J Org Chem. 2016 Apr 8. [Epub ahead of print]
Diindenopyrene 4b and its diastereomer, which are extended homologues of 1,6- and 1,8-pyrenoquinodimethanes fused by indene units, respectively, were synthesized by reaction of 1,4,5,8-tetrakis(mesitylethynyl)naphthalene (7) with bis(2,4,6-trimethylpyridine)iodine(I) hexafluorophosphate via cationic cyclization mechanisms at both centers of reaction. Unexpectedly, reaction of 7 with iodine, a reagent that typically gives products of cationic cyclization, gave cycloheptapentalenoindenophenalene derivative 9b and its diastereomer incorporating an azulene unit at one end of the π framework, via two different modes (radical and cationic) of cyclization at each reaction site. The physical properties of the products are presented, and the dual modes of cyclization of 7 and its model compound with only one reaction center are discussed.
