Complete Photochemical Regulation of 8–17 DNAzyme Activity by Using Reversible DNA Photo-crosslinking

The regulation of DNAzyme activity is an important problem for its in vivo applications. We achieved photochemical regulation of DNAzyme activity by using reversible DNA photo-crosslinking of 3-cyanovinylcarbazole (^CNVK). The ODN containing ^CNVK photo-crosslinked to a pyrimidine base in the complementary strand after a few seconds of photoirradiation, and its photoadduct was split by photoirradiation of another wavelength. The activity of photo-crosslinked DNAzyme with ^CNVK was completely inhibited (OFF state). In contrast, after 312 nm irradiation, DNAzyme activity was recovered upon addition of a substrate strand (ON state). In addition, the photo-crosslinked DNAzyme is prone to enzymatic digestion by exonuclease. This photochemical OFF to ON switching with reversible DNA photo-crosslinking was regulated at the desired time and position; therefore, it might be possible to use it for in vivo application.     

Supramolecular Ligands for Histone Tails by Employing a Multivalent Display of Trisulfonated Calix[4]arenes

Post‐translational modification of histone tails plays critical roles in gene regulation. Thus, molecules recognizing histone tails and controlling their epigenetic modification are desirable as biochemical tools to elucidate regulatory mechanisms. There are, however, only a few synthetic ligands that bind to histone tails with substantial affinity. We report CA2 and CA3, which exhibited sub‐micromolar affinity to histone tails (especially tails with a trimethylated lysine). Multivalent display of trisulfonated calix[4]arene was important for strong binding. CA2 was applicable not only to synthetic tail peptides but also to endogenous histone proteins, and was successfully used to pull‐down endogenous histones from nuclear extract. These findings indicate the utility of these supramolecular ligands as biochemical tools for studying chromatin regulator protein and as a targeting motif in ligand‐directed catalysis to control epigenetic modifications.     

Scaling up experiments of honeycomb catalysts for oxidation of hydrogen and methane gases

For a large volume air cleanup system in nuclear fusion facility honeycomb type oxidizing catalyst offers more useful advantage in terms of their low pressure drop than the conventional particle packed bed. Scaling up examination of 35 times large volume Pd catalyst deposit on metal honeycomb Al–Cr-steel alloy had been performed comparing with fundamental small size honeycomb. The catalyst was heated up to over 400 °C with stepwise by combined the inner and external heaters under various flow rate of processing gas containing various concentrations of hydrogen and methane. Then oxidizing reaction rates and the catalytic activation energies were evaluated and thermal property of catalyst bed was estimated considering exothermic oxidizing reaction in the process gas. As a result it was revealed that the scaling up honeycomb catalyst bed would be practically useful for the air cleanup system.     

Transient power characteristics of balanced three‐phase variable inductance

Inductance has a particularly important role in power circuits. The authors have proposed the Variable Active–Passive Reactance (VAPAR), which can produce a virtual variable inductance. In this paper, the transient power characteristics of a balanced three‐phase variable inductance are analyzed using the instantaneous active and reactive power theorem. With an ideal voltage source or an ideal current source connected to a balanced three‐phase variable inductance, the transient power characteristics are analyzed theoretically, and then the results are verified through simulations. In the other cases, it is difficult to solve for the transient power, but it is shown that the transient power characteristics can easily be estimated from the results of simulations in which an ideal voltage source or an ideal current source is connected to a balanced three‐phase variable inductance. Experiments are also carried out to verify the theoretical analysis and simulations. © 2001 Scripta Technica, Electr Eng Jpn, 136(2): 49–57, 2001     

Processability and mechanical properties for binary blends of PP and LLDPE produced by metallocene catalyst

Processability at extrusion coating and mechanical properties of the films obtained are investigated by means of linear and nonlinear rheological measurements and tensile tests for blends of polypropylene (PP) and linear low‐density polyethylene (LLDPE). Both materials are produced by metallocene catalyst. The processability of PP is found to be improved by the addition of LLDPE; the blend shows low level of motor torque and head pressure in an extruder and small level of neck‐in as compared with pure PP. Further, the anisotropy of ultimate tensile strength, which is prominent for PP, is reduced by blending with LLDPE. As a result, the blend having 20 wt % of LLDPE shows appropriate properties in the molten state for extrusion coating and in the solid state as a film. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Frictional properties of diamond-like carbon, glassy carbon and nitrides with femtosecond-laser-induced nanostructure

This paper reports macro and micro frictional properties of DLC, TiN, CrN films and GC substrate of which surfaces are nanostructured with femtosecond (fs) laser pulses. The friction coefficient μ of the nanostructured surface was measured at a usual load with a ball-on-disk friction test machine. The results have shown that carbon materials of DLC and GC provide lower values of μ than TiN and CrN, and μ of DLC and TiN measured with a hardened steel ball decreases with an increase of the laser pulse energy. On the other hand, μ of nanostructured surfaces of thin films monotonously increases with an increase in laser pulse energy, which was measured with a micro-scratch test at an ultralight load of 1.5 mN utilizing a diamond tip. The friction coefficient of the GC substrate irradiated at a low fluence around the ablation threshold has shown a lower value than that of the non-irradiated surface.     

Polyacrylonitrile/Nylon 6 Blends: Preparation and Characterization

Summary: Polyacrylonitrile (PAN) particles with micro‐size ranges (0.15–2 μm) were prepared by emulsion and dispersion polymerizationa and in supercritical carbon dioxide media. The PAN particles were blended with Nylon 6 (PA6) at 220 °C by using a miniature mixer; it was found that melt‐mixing was possible for PAN‐rich compositions as high as 70 wt.‐%. Blends were characterized by scanning electron microscopy, IR, viscosity measurements, differential scanning calorimetry, and dynamic mechanical thermal analysis (DMTA). The size and shape of original PAN particles were retained in PAN/PA6 blends. The useful range to blend PAN particles size was less than 1 μm in terms of shape retention of the PAN particles in blends. Blends with 40 wt.‐% PAN content were found to be melt‐processable. The elastic modulus was higher for PAN/PA6 blends than pure PA6.

SEM photograph of PAN‐SC/PA6 blend with a 40/60 weight ratio.     

Comparison of enteral nutrition with combined enteral and parenteral nutrition in post-pancreaticoduodenectomy patients: a pilot study

Background  

Many clinical studies have demonstrated that early postoperative enteral nutrition (EN) improved the postroperative course. Post-pancreaticoduodenectomy (PD), patients tend to suffer from postoperative nausea, abdominal distention, and diarrhoea, causing difficulty in the introduction of EN. In this pilot study, we investigated the appropriate nutritional mode post-pancreatic surgery.     

Discussion on the equivalent conductivity and resistance of stress corrosion cracks in eddy current simulations

This study evaluates the numerical modeling of stress corrosion cracks from the viewpoint of eddy current simulations. Five stress corrosion cracks are artificially introduced into austenitic stainless steel plates measuring 25 mm in thickness, and then eddy current inspections are conducted to gather eddy current signals and destructive tests performed to confirm the true profiles of the cracks. The cracks are carefully introduced so as not to cluster, and the data obtained enables discussion of the modeling of a single crack quantitatively. Subsequent numerical simulations model each crack as a rectangular region with a fixed width and uniform conductivity, and evaluate the equivalent width and conductivity suitable for modeling the crack. The evaluation reveals that it is not reasonable to correlate the size of a crack and only its width or conductivity, and larger cracks tend to have greater resistance, which is defined as the width divided by conductivity. Furthermore, the values of width and conductivity depend also on the exciting frequency and probe used; however, the resistance remains almost unchanged by the experimental condition.