Light and heavy hadron masses in a relativistic quark potential model with diquark clustering

Meson masses are calculated in the quark model with a phenomenological spin-dependent potential of form motivated by QCD. For comparison, the potential is used in two different wave equations, both of which incorporate the feature of relativistic two-body kinematics. The masses of light and heavy pseudoscalar and vector mesons are calculated in the model with only a small number of adjustable parameters, and good qualitative agreement with experiment is obtained. The masses of diquarks are calculated without any additional parameters, using the same potential as for mesons except for a QCD color factor. Then baryon masses are calculated, also without additional parameters, in an approximation in which a baryon is a composite of a quark and a diquark. Again the results are in good qualitative agreement with experiment. Both wave equations yield similar solutions, although there are differences in detail. One distinctive feature of the model is that quark current masses are used as input, and effective constituent quark masses are obtained as a result of the calculation.     

Uniaxial drawing of poly[(R)-3-hydroxybutyrate]/cellulose acetate butyrate blends and their orientation behavior

Miscible blends of PHB and CAB were prepared by the solvent-casting method with various blend compositions, and their orientation behavior was investigated during uniaxial drawing. X-ray analysis revealed that the orientation of the crystallizable PHB component in the drawn PHB/CAB blends was changed from c-axis-orientation to a-axis-orientation with increasing CAB content. The a-axis-orientation was a result from the a-axis-oriented crystal growth caused by the intramolecular nucleation and the confined crystal growth. For quantitative assessment of the chain orientation, the Hermans orientation functions of the two respective components were obtained from the polarized FT-IR measurements. The orientation function of pure PHB stretched to 5 times of its initial length was approximately 0.8. However the value decreased rapidly with increasing CAB content, and it turned to a negative value from 30 wt.-% CAB content. This indicates that the PHB chains were aligned perpendicular to the drawing direction. On the contrary, the value of the CAB component remained almost unchanged at about 0.1 regardless of the blend composition and the annealing time, indicating that the CAB chains were constantly oriented parallel to the drawing direction without any chain relaxation. In addition, SAXS analysis suggested that the lamellar stacking direction also changed from parallel to perpendicular in the stretching direction with increasing CAB content.     

"Bioelectronic super-taster" device based on taste receptor-carbon nanotube hybrid structures

We have developed a method to monitor the activities of human taste receptor protein in lipid membrane using carbon nanotube transistors, enabling a "bioelectronic super-taster (BST)", a taste sensor with human-tongue-like selectivity. In this work, human bitter taste receptor protein expressed in E. coli was immobilized on a single-walled carbon nanotube field effect transistor (swCNT-FET) with the lipid membrane. Then, the protein binding activity was monitored using the underlying swCNT-FET, leading to the operation as a BST device. The fabricated BST device could detect bitter tastants at 100 fM concentrations and distinguish between bitter and non-bitter tastants with similar chemical structures just like a human tongue. Furthermore, this strategy was utilized to differentiate the responses of taster or non-taster types of the bitter taste receptor proteins.