Real-time line projection for fast terahertz spectral computed tomography

We demonstrated fast terahertz spectral computed tomography by using real-time line projection of a terahertz beam. Two types of cross-sectional images of continuously rotating samples have been measured in only a few seconds. From temporal data, a peak-to-peak sinogram and cross sections have been reconstructed using a filtered backprojection algorithm. Using fast Fourier transform from temporal data, spectral cross sections of the sample have been obtained.     

Effect of uniaxial stress on ionic conductivity of 14 mol%-yttria-stabilized zirconia single crystal

In the present study, the ionic conductivity of the 14 mol%-yttria stabilized zirconia single crystal subjected to the tensile or compressive stress was examined at various temperatures. The conductivity was increased by the tensile stress and the improvement in the conductivity was higher at the lower temperature and also for the specimen with the <100> orientation. On the other hand, the conductivity was decreased by the compressive stress. The change by the compressive stress was higher at the lower temperature, but it was generally smaller than that in the tensile test. The maximum improvement achieved by applying the tensile stress was about 18% at 850 K in the present study. The present experimental results qualitatively agreed with the molecular dynamics simulations on the oxygen diffusion. The oxygen displacement in the fluorite lattice caused by the applied stress could be attributed to the change in the conductivity.     

Total syntheses of (-)- and (+)-goniomitine

The Stille coupling reaction of 3-(benzyloxymethyl)-1-(tert-butyldiphenylsiloxy)ethyl-1-(tributylstannyl)allene with N-(tert-butoxycarbonyl)-2-iodoaniline directly produced the corresponding 2-vinylindole derivative, which was independently transformed into natural (-)-goniomitine and unnatural (+)-goniomitine via the cross-metathesis with chiral oxazolopiperidone lactams. The antiproliferative activity of the synthesized natural (-)-goniomitine in Mock and MDCK/MDR1 cells showed them to be more potent to retard cell growth than unnatural (+)-goniomitine.     

Copper-catalyzed carboxylation of alkylboranes with carbon dioxide: formal reductive carboxylation of terminal alkenes

Carboxylation of alkylboron compounds (alkyl-9-BBN) with CO(2) proceeded in the presence of catalytic amounts of CuOAc/1,10-phenanthroline and a stoichiometric amount of KO(t)Bu. The alkylboranes are easily and widely available through the alkene hydroboration, and thus the overall process represents a reductive carboxylation of alkenes with CO(2). The broad functional group compatibility and the inexpensiveness of the Cu/1,10-phenathoroline catalyst system are attractive features of this protocol.     

Enzyme-immobilized microfluidic process reactors

Microreaction technology, which is an interdisciplinary science and engineering area, has been the focus of different fields of research in the past few years. Several microreactors have been developed. Enzymes are a type of catalyst, which are useful in the production of substance in an environmentally friendly way, and they also have high potential for analytical applications. However, not many enzymatic processes have been commercialized, because of problems in stability of the enzymes, cost, and efficiency of the reactions. Thus, there have been demands for innovation in process engineering, particularly for enzymatic reactions, and microreaction devices represent important tools for the development of enzyme processes. In this review, we summarize the recent advances of microchannel reaction technologies especially for enzyme immobilized microreactors. We discuss the manufacturing process of microreaction devices and the advantages of microreactors compared to conventional reaction devices. Fundamental techniques for enzyme immobilized microreactors and important applications of this multidisciplinary technology are also included in our topics.     

On-chip magnetically actuated robot with ultrasonic vibration for single cell manipulations

This paper presents an innovative driving method for an on-chip robot actuated by permanent magnets in a microfluidic chip. A piezoelectric ceramic is applied to induce ultrasonic vibration to the microfluidic chip and the high-frequency vibration reduces the effective friction on the MMT significantly. As a result, we achieved 1.1 micrometre positioning accuracy of the microrobot, which is 100 times higher accuracy than without vibration. The response speed is also improved and the microrobot can be actuated with a speed of 5.5 mm s(-1) in 3 degrees of freedom. The novelty of the ultrasonic vibration appears in the output force as well. Contrary to the reduction of friction on the microrobot, the output force increased twice as much by the ultrasonic vibration. Using this high accuracy, high speed, and high power microrobot, swine oocyte manipulations are presented in a microfluidic chip.     

Photorearrangements in spiro-conjoined cyclohexa-2,5-dien-1-one

The unexpected formation of cyclohexa-2,5-dien-1-one (6) spiro-conjoined with a dihydrobenzofuran framework, and the photochemical behavior of this compound in solution as well as in the solid state are described. The photoreaction of 6 in solution affords two rearranged products, one (7) accompanied by the enlargement of the oxygen heterocyclic ring and the other (8) accompanied by cyclopentadienone fragmentation. In the solid state, the former is the sole photoproduct of both solvated and desolvated crystals. The desolvated crystals were obtained as polycrystalline solids by thermal release of solvent molecules, and its structure was elucidated by ab initio determination from X-ray powder diffraction data followed by the Rietveld refinement.     

Study on the spin-crossover transition in [Fe(cis-/trans-stpy)4(X)2] (stpy: styrylpyridine, X: NCS, NCBH3) under high pressure toward ligand-driven light-induced spin change

Toward the realization of a ligand-driven light-induced spin change (LD-LISC) around room temperature, we have investigated the spin-crossover phenomenon in [Fe(stpy)₄(X)₂] (stpy = styrylpyridine, X = NCS, NCBH₃) under high pressure. The spin transition temperature increases from 110 to 220 K with increasing applied pressure up to 0.75 GPa for [Fe(trans-stpy)₄(NCS)₂], while [Fe(cis-stpy)₄(NCS)₂] shows the high-spin state in the temperature region between 2 and 300 K even at 0.75 GPa. In the case of X = NCBH₃, due to the stronger ligand field of NCBH₃, the spin transition temperature increases from 240 to 360 K with increasing applied pressure up to 0.50 GPa for [Fe(trans-stpy)₄(NCBH₃)₂]. In the case of [Fe(cis-stpy)₄(NCBH₃)₂], the spin state is the high-spin state in the temperature region between 2 and 300 K. However, the spin transition appears at 125 K under 0.5 GPa and the transition temperature increases with increasing applied pressure. In this way, we have decided the applied pressure region of 0.65-1.09 GPa where [Fe(stpy)₄(NCBH₃)₂] undergoes LD-LISC at room temperature.