Food structure: Roles of mechanical properties and oral processing in determining sensory texture of soft materials

There is a desire to alter food composition to make foods healthier and at the same time not diminish sensory quality. This requires an understanding of key elements of food structure associated with texture perception. Texture, in part, is perceived during oral processing of food. Knowledge of structure–oral processing–texture interrelations could be utilized to develop or prevent specified textural attributes. Overall, the investigation of structure–oral processing–texture interrelations is just starting as a research focus. Factors including non-universal and inconsistent sensory terminology, omission of consideration for structural changes incurred by oral processes, and the lack of cross-disciplinary investigations hamper progress in this field. Consideration of these factors in future investigations on sensory texture will increase the applicability of their findings and bring us closer to understanding the contribution of food structure to sensory texture.     

Observation of insulating–insulating monoclinic structural transition in macro‐sized VO2 single crystals [Phys. Status Solidi RRL 5, No. 3, R107–R109 (2011)]

In our article, we reported the observation of monoclinic M2 to M1 structural phase transition in VO₂ single crystal near the temperature of ～49 °C. However, the re‐examination of Laue patterns reveals that previously defined monoclinic M1 and M2 phases can be interpreted as monoclinic M2 and triclinic T phases instead. Careful experimental geometry calibration and further refinement of the lattice parameter ratios and angles show that monoclinic M2 and triclinic T phases fit better with the experimental data. On the other hand, our previous misidentification of the insulating phases does NOT affect the conclusions of our article. (© 2015 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim)     

Thiophene isosteres of 9,10-dithioanthraquinone

[reaction: see text] The preparation of 1,3,5,7-tetramethyl-4,8-dihydrobenzo[1,2-c:4,5-c']dithiophene-4,8-dione and its conversion to the corresponding mono- and dithione are described.     

Processive replication of single DNA molecules in a nanopore catalyzed by phi29 DNA polymerase

Coupling nucleic acid processing enzymes to nanoscale pores allows controlled movement of individual DNA or RNA strands that is reported as an ionic current/time series. Hundreds of individual enzyme complexes can be examined in single-file order at high bandwidth and spatial resolution. The bacteriophage phi29 DNA polymerase (phi29 DNAP) is an attractive candidate for this technology, due to its remarkable processivity and high affinity for DNA substrates. Here we show that phi29 DNAP-DNA complexes are stable when captured in an electric field across the α-hemolysin nanopore. DNA substrates were activated for replication at the nanopore orifice by exploiting the 3'-5' exonuclease activity of wild-type phi29 DNAP to excise a 3'-H terminal residue, yielding a primer strand 3'-OH. In the presence of deoxynucleoside triphosphates, DNA synthesis was initiated, allowing real-time detection of numerous sequential nucleotide additions that was limited only by DNA template length. Translocation of phi29 DNAP along DNA substrates was observed in real time at ?ngstrom-scale precision as the template strand was drawn through the nanopore lumen during replication.     

Synthesis of 5,10-dideazaminopterin

The synthesis of 5,10-dideazaaminopterin by two independent routes is described. Condensation of the piperidine enamine of 4-p-carbomethoxyphenylbutyraldehyde ( 4 ) with ethoxymethylenemalononitrile followed by treatment of the resultant arylethylenaminomalononitrile ( 5 ) with methanolic ammonia produced 2-amino-3-cyano-5-p-carbomethoxyphenethylpyridine ( 6 ). Cyclization of the aminocyanopyridine with guanidine afforded 4-amino-4-deoxy-5,10-dideazapteroic acid ( 8 ). Coupling of the pteroate intermediate with glutamate yielded the target 5,10-dideazaaminopterin ( 10 ). Alternatively, reduction of 2,4-diamino-6-formyl-5-deazapteridine ( 11 ) with sodium borohydride gave the 6-hydroxymethyl compound 12 . Conversion to the bromide was followed by alkylation of dimethyl homoterephthalate to afford methyl 4-amino-4-deoxy-10-carbomethoxy-5,10-dideazapteroate ( 14 ). Decarboxylation with ester cleavage (sodium cyanide in dimethyl sulfoxide at 180°) also gave the diaminopteroic acid ( 8 ). 5,10-dideazaaminopterin ( 10 ) was an effective growth inhibitorof folate dependent bacteria, S. faecium and L. casei.     

Benzophenone absorption and diffusion in poly(dimethylsiloxane) and its role in graft photo-polymerization for surface modification

Following the great success of traditional microfluidic devices across many disciplines, a new class of microfluidic systems emerged in recent years, which features finely tuned, localized surface modifications within the microstructures in order to keep up with the demand for devices of ever increasing complexity (lab on chip, assay on chip, etc.). Graft photopolymerization has become a powerful tool for such localized surface modifications particularly in combination with poly(dimethylsiloxane) (PDMS) devices, as it is compatible with many functional monomers and allows for high spatial resolution. However, application within enclosed PDMS microstructures and in particular well-controlled surface-directed polymerization remains challenging. Detailed understanding of the interaction between photoinitiator, benzophenone (BP), and polymer matrix is needed. We have developed a visualization technique, which allows for observation of reacted BP in situ within the PDMS matrix. We present a detailed study on solvent-driven BP diffusion providing results essential to successful surface treatment. We also identified and investigated photoinitiator inhibition by oxygen and provide appropriate mitigation strategies.