Development of a fluorescence peptide chip for the detection of caspase activity

Proteases play a key role in cell functions, and it is very important to monitor their activities for drug screening and diagnosis of diseases. In the present study, a new class of fluorescence probe, into which a fluorophore and a quencher have been introduced, was developed and applied to the on-chip detection of caspase-3 activity. This probe is non fluorescent in the absence of caspase-3. However, when it is treated with active caspase-3, the fluorescence intensity increases dependent on the caspase-3 activity due to the cleavage of the quencher-containing moiety on a glass slide. This caspase-dependent increase in the fluorescence intensity was also detected when the glass slide immobilizing the probe peptide was treated with cell lysate stimulated by staurosporine (STP), which is an apoptosis-inducing agent. On the other hand, such an increase was not detected in the case of control cell lysate without STP-stimulation. The developed system is a rapid and sensitive method and is useful for the direct measurement of protease activity on a glass array.     

Two-directional synthesis and stereochemical assignment toward a C2 symmetric oxasqualenoid (+)-intricatetraol

The asymmetric synthesis of tetraol (+)-3, a degradation product derived from a C2 symmetric oxasqualenoid intricatetraol 1, has been achieved through the two-directional synthesis starting from diol 7, realizing the further additional assignment of the incomplete stereostructure of 1, the stereochemistry of which is difficult to determine otherwise.     

An analytical approach to determine the pore shape and size of MCM-41 materials from X-ray diffraction data

The pore shape and size of MCM-41 were studied analytically by comparing the observed powder X-ray diffraction intensities with that derived from the MCM-41 crystal structure models, with two different pore shapes, a hexagon and a circle. The powder diffraction patterns from the as-synthesized and the calcined MCM-41 were measured by a synchrotron radiation at SPring-8, Japan. The MCM-41 structure with circular and hexagonal pore shapes explains well for the as-synthesized and the calcined MCM-41 crystals, respectively. The pore size and boundary obtained by this approach agree with those obtained from an N2 gas adsorption measurement combined with the Fourier synthesized density map.     

Raman spectroscopy of optically levitated supercooled water droplet

By use of an optical trap, we can levitate micrometer-sized drops of purified water and cool them below the melting point free from contact freezing. Raman spectra of the OH stretching band were obtained from those supercooled water droplets at temperatures down to -35 °C. According to the two-state model, an enthalpy change due to hydrogen-bond breaking is derived from temperature dependence of the spectral profile. The isobaric heat capacity calculated from the enthalpy data shows a sharp increase as the temperature is lowered below -20 °C in good agreement with conventional thermodynamic measurements.     

Designing of interference pattern in ultra-short pulse laser processing

We have studied material processing by using an interfering ultra-short pulse laser. In this process, an interference pattern is transferred to material surface, and a periodic structure can be generated in a single shot of laser irradiation. Here, it is well known that the period of the interference pattern can be controlled by correlation angle and wavelength. In addition, a composite, doubled in density or designed interference pattern can be formed by controlling the phase shift and variation of amplitude between the interfering laser beams. In this paper, basic patterns of interference are summarized in the case of four-beam correlation.     

Quantitative image reconstruction of GaN quantum dots from oversampled diffraction intensities alone

The missing data problem, i.e., the intensities at the center of diffraction patterns cannot be experimentally measured, is currently a major limitation for wider applications of coherent diffraction microscopy. We report here that, when the missing data are confined within the centrospeckle, the missing data problem can be reliably solved. With an improved instrument, we recorded 27 oversampled diffraction patterns at various orientations from a GaN quantum dot nanoparticle and performed quantitative image reconstruction from the diffraction intensities alone. This work in principle clears the way for single-shot imaging experiments using x-ray free electron lasers.     

Synthesis of Optically Active,X‐Shaped,Conjugated Compounds and Dendrimers Based on Planar Chiral [2.2]Paracyclophane,Leading to Highly Emissive Circularly Polarized Luminescence

Optically active, Fréchet‐type dendrimers containing an emissive X‐shaped π‐electron system as the core unit were synthesized. Gram‐scale optical resolution and transformations of 4,7,12,15‐tetrasubstituted [2.2]paracyclophanes were also carried out. The high‐generation dendrons effectively absorbed UV light and transferred energy to the core, resulting in high photoluminescence (PL) from the core. In addition, the dendrons sufficiently isolated the emissive X‐shaped conjugated core and bright emission was observed from both thin films and solutions. Intense circularly polarized luminescence (CPL) was observed from the thin film. The dendrimer films exhibited excellent optical properties, such as large molar extinction coefficients, high fluorescence quantum efficiencies, intense PL and CPL, and large CPL dissymmetry factors.