A method for determining absolute configuratiom of β-amino acids by CD spectra of their DNP derivatives

Aromatic β-amino acids were converted to the Dnp derivatives, and aliphatic ones to Dnp-pMA derivatives. The sign of the Cotton effect near 400 nm reflected the configuration at the β-position without exception. Thus, the relation seems to afford a new reliable method for determining the absolute configuration of β-amino acids.     

Positive muon behavior in KCl with and without F centers

Positive muon behavior in KCl containing F centers has been studied. The muon spin depolarization rate showed a maximum near 120 K, which was not found in pure KCl. This is probably due to the fact that free positive muons are trapped by F centers in KCl. However, the binding energy between a positive muon and an F center is not large, so that muons detrap again above 150 K.     

SDP reformulation for robust optimization problems based on nonconvex QP duality

In a real situation, optimization problems often involve uncertain parameters. Robust optimization is one of distribution-free methodologies based on worst-case analyses for handling such problems. In this paper, we first focus on a special class of uncertain linear programs (LPs). Applying the duality theory for nonconvex quadratic programs (QPs), we reformulate the robust counterpart as a semidefinite program (SDP) and show the equivalence property under mild assumptions. We also apply the same technique to the uncertain second-order cone programs (SOCPs) with “single” (not side-wise) ellipsoidal uncertainty. Then we derive similar results on the reformulation and the equivalence property. In the numerical experiments, we solve some test problems to demonstrate the efficiency of our reformulation approach. Especially, we compare our approach with another recent method based on Hildebrand’s Lorentz positivity.     

Establishing Nash equilibrium of the manufacturer–supplier game in supply chain management

We study a game model of multi-leader and one-follower in supply chain optimization where n suppliers compete to provide a single product for a manufacturer. We regard the selling price of each supplier as a pre-determined parameter and consider the case that suppliers compete on the basis of delivery frequency to the manufacturer. Each supplier's profit depends not only on its own delivery frequency, but also on other suppliers' frequencies through their impact on manufacturer's purchase allocation to the suppliers. We first solve the follower's (manufacturer's) purchase allocation problem by deducing an explicit formula of its solution. We then formulate the n leaders' (suppliers') game as a generalized Nash game with shared constraints, which is theoretically difficult, but in our case could be solved numerically by converting to a regular variational inequality problem. For the special case that the selling prices of all suppliers are identical, we provide a sufficient and necessary condition for the existence and uniqueness of the Nash equilibrium. An explicit formula of the Nash equilibrium is obtained and its local uniqueness property is proved.     

Measuring tongue motion from tagged cine-MRI using harmonic phase (HARP) processing

A cine series of tagged magnetic resonance (MR) images of the tongue is used to measure tongue motion and its internal deformation during speech. Tagged images are collected in three slice orientations (sagittal, coronal, and axial) during repetitions of the utterance "disouk" (/disuk/). A new technique called harmonic phase MRI (HARP-MRI) is used to process the tagged MR images to measure the internal deformation of the tongue. The measurements include displacement and velocity of tissue points, principal strains, and strain in the line-of-action of specific muscles. These measurements are not restricted to tag intersections, but can be calculated at every pixel in the image. The different motion measurements complement each other in understanding the tongue kinematics and in hypothesizing the internal muscle activity of the tongue.     

Two-photon fluorescence bioimaging with an all-semiconductor laser picosecond pulse source

We have demonstrated successful two-photon excitation fluorescence bioimaging using a high-power pulsed all-semiconductor laser. Toward this purpose, we developed a pulsed light source consisting of a mode-locked laser diode and a two-stage diode laser amplifier. This pulsed light source provided optical pulses of 5 ps duration and having a maximum peak power of over 100 W at a wavelength of 800 nm and a repetition frequency of 500 MHz.