Mechano-Optical Sensors Fabricated with Multilayered Liquid Crystal Elastomers Exhibiting Tunable Deformation Recovery

Advances in tuning the mechanoresponsive behavior of liquid crystal elastomers have facilitated the development of next-generation applications such as reconfigurable photonic/electronic materials, energy-harvesting devices, and flexible sensors. However, the molecular-level control of mechanical responses remains difficult, with limited tunability achieved for recovery processes after stimulus removal. Herein, a design concept is proposed for facilely tuning the recovery of both the macroscopic deformation and molecular orientation change of liquid crystal elastomers using layered materials that exhibit the desired mechanoresponsive behavior. Changing the layering materials (a polydimethylsiloxane film with elastic response to a polymethylpenten film with plastic response) alters the relaxation time from <1 s to >6 months. To demonstrate this concept, highly sensitive, stretchable mechano-optical sensors with fast and ultraslow recovery times are developed that enable an applied strain to be quantitatively detected in real time or memorized with high spatial resolution, even with a conventional camera. This material design concept for arbitrarily controlling the recovery response can provide a platform for stimuli-responsive applications.     

Modification of the carbonization properties of coal-tar pitch by supercritical fluid extraction

The carbonization properties of coal-tar pitch were modified by supercritical fluid (SCF) extraction. Pitches extracted with supercritical toluene (SCFE pitch) contained none of the quinoline insoluble (QI) matter responsible for anisotropic structures with small unit sizes. The size of anisotropic structures from SCFE pitches was closely related to the β-resin (toluene insoluble and quinoline soluble fraction) content. Anisotropic structures from blended pitches prepared to have the same β-resin content as SCFE pitches (by blending toluene soluble (TS) and β-resin fractions obtained through a conventional liquid solvent extraction) were smaller. Extraction of the β-resin fraction with supercritical toluene could be interpreted by the co-solvent effects of the TS fraction dissolved in the extract phase. The high concentration of TS fraction in the extract phase enhanced the solubility of the β-resin fraction into this phase. In the raffinate phase, the heavier β-resin components, which are unsuitable for the development of mesophase structures, coagulated and formed unextractable QI matter through reduction in the concentration of the TS fraction. Since the TS concentration in both the phases depends on pressure and the ratio of the amounts of supercritical toluene and pitch, the control of the β-resin content in the SCFE pitches is possible through the adjustment of these two parameters.     

Distributed parameter analysis for the prediction of the fine structure of flow and temperature fields in wire-wrapped fuel pin bundle geometries

This paper describes the numerical method of a distributed parameter analysis code SPIRAL for the calculation of fluid flow and temperature in arbitrary channel geometries, discusses the numerical method in the modeling and solution of the problem, and presents some results, including comparison with experiments.

The derivation and solution of the finite element equations is discussed. In order to overcome difficulties arising from the geometry, the Galerkin finite element method using isoparametric elements was employed, and a procedure of finite element generation using curvilinear coordinate system was developed.

The SPIRAL code permits calculation of the fine structure of the multi-dimensional steady-state single-phase fluid flow and temperature fields in LMFBR fuel pin subassemblies in the presence of wire spacers. Calculated results are presented for crossflow velocity distributions and crossflow pressure drop characteristics in a tube bundle geometry with and without wire spacers, natural convection and heat transfer in horizontal annuli, flow in a wire-wrapped 7-pin bundle geometry and fully developed turbulent flow in a parallel 4-rod array contained in a rectangular duct.     

Synthesis of V-MCM-41 by template-ion exchange method and its catalytic properties in propane oxidative dehydrogenation

Vanadium has been introduced to MCM-41 without collapse of the mesoporous structure by exchanging VO²+ ions in the aqueous solution with the template cations in the uncalcined MCM-41. This template-ion exchange (TIE) method provides tetrahedrally coordinated vanadyl species dispersed in the channel of MCM-41. Such synthesized V-MCM-41 shows higher catalytic activity in the oxidative dehydrogenation of propane than that prepared by direct hydrothermal method.     

Identification of Chimeric αβγ Diterpene Synthases Possessing both Type II Terpene Cyclase and Prenyltransferase Activities

Two unusual diterpene synthases composed of three domains (α, β, and γ) were identified from fungal Penicillium species. They are the first enzymes found to possess both type II terpene cyclase (TC) and prenyltransferase (PT) activities. These enzymes were characterized by heterologous expression in Aspergillus oryzae and in vitro experiments with wild-type, mutated, and truncated enzymes. The results revealed that the α domain in the C-terminal region of these enzymes was responsible for the PT activity, whereas the βγ domains in the N-terminal region composed the type II TC, and formed copalyl diphosphate ( 2 ). Additionally, between the α and βγ domains, there is a characteristic linker region, in which minimal secondary structure is predicted. This linker does not exist in the characterized three-domain (αβγ) terpene synthases known as monofunctional type I or type II TCs, or bifunctional type I and type II TC enzymes. Therefore, both the catalytic activities and protein architecture substantially differentiate these new enzymes from the previously characterized terpene synthases.     

Structural Diversification of Lyngbyatoxin A by Host‐Dependent Heterologous Expression of the tleABC Biosynthetic Gene Cluster

Natural products have enormous structural diversity, yet little is known about how such diversity is achieved in nature. Here we report the structural diversification of a cyanotoxin—lyngbyatoxin A—and its biosynthetic intermediates by heterologous expression of the Streptomyces‐derived tleABC biosynthetic gene cluster in three different Streptomyces hosts: S. lividans, S. albus, and S. avermitilis. Notably, the isolated lyngbyatoxin derivatives, including four new natural products, were biosynthesized by crosstalk between the heterologous tleABC gene cluster and the endogenous host enzymes. The simple strategy described here has expanded the structural diversity of lyngbyatoxin A and its biosynthetic intermediates, and provides opportunities for investigation of the currently underestimated hidden biosynthetic crosstalk.     

New pixel circuits for controlling threshold voltage by back‐gate bias voltage using crystalline oxide semiconductor FETs

We devised a threshold voltage compensation pixel circuit using back‐gate bias voltage. Variation in threshold voltages can be reduced to 10% in simulation while improving the saturation characteristics of a driving transistor. The pixel circuit can compensate not only threshold variation but also mobility variation. We fabricated a 5.29‐in Quad‐VGA organic light emitting diode display using this pixel circuit.     

Evaluation of autotrophic growth of ammonia-oxidizers associated with granular activated carbon used for drinking water purification by DNA-stable isotope probing

Nitrification is an important biological function of granular activated carbon (GAC) used in advanced drinking water purification processes. Newly discovered ammonia-oxidizing archaea (AOA) have challenged the traditional understanding of ammonia oxidation, which considered ammonia-oxidizing bacteria (AOB) as the sole ammonia-oxidizers. Previous studies demonstrated the predominance of AOA on GAC, but the contributions of AOA and AOB to ammonia oxidation remain unclear. In the present study, DNA-stable isotope probing (DNA-SIP) was used to investigate the autotrophic growth of AOA and AOB associated with GAC at two different ammonium concentrations (0.14 mg N/L and 1.4 mg N/L). GAC samples collected from three full-scale drinking water purification plants in Tokyo, Japan, had different abundance of AOA and AOB. These samples were fed continuously with ammonium and ¹³C-bicarbonate for 14 days. The DNA-SIP analysis demonstrated that only AOA assimilated ¹³C-bicarbonate at low ammonium concentration, whereas AOA and AOB exhibited autotrophic growth at high ammonium concentration. This indicates that a lower ammonium concentration is preferable for AOA growth. Since AOA could not grow without ammonium, their autotrophic growth was coupled with ammonia oxidation. Overall, our results point towards an important role of AOA in nitrification in GAC filters treating low concentration of ammonium.     

Memory effect-enhanced catalytic ozonation of aqueous phenol and oxalic acid over supported Cu catalysts derived from hydrotalcite

Mg/Al supported metal (Fe, Co, Ni and Cu) oxide catalysts were prepared by co-precipitation of hydrotalcite-like clay materials as precursors, calcined, and used for the ozonation reaction of phenol and oxalic acid. The reaction was carried out using the catalyst and aqueous solution of phenol or oxalic acid in an O₃/O₂ mixed gas-flow at 20 °C. In the ozonation of phenol, the combination of ozone and supported metal oxide catalysts was effective for the removal of total organic carbon (TOC). Also in the ozonation of oxalic acid as the main TOC component, Cu/Mg/Al catalysts showed the highest activity, followed by Ni/Mg/Al catalyst, while both Fe/Mg/Al and Co/Mg/Al catalysts were not active. Leaching of Cu and Ni, probably due to the chelation of metals by oxalic acid, was significantly observed at the beginning of the reaction. However the metal leaching disappeared at the end of the reaction possibly due to the entire consumption of oxalic acid during the reaction. The best result of oxalic acid mineralization was observed over Cu/Mg/Al catalyst calcined at 600 °C, on which least leaching of the metal was detected. Moreover, a “memory effect” of hydrotalcite accelerated the mineralization of oxalic acid over the Cu/Mg/Al catalyst; oxalate anions were captured and decomposed in the reconstituted hydrotalcite interlayer space on the surface of the Cu/Mg/Al catalyst, resulting in a remarkable enhancement in the catalytic activity of the ozonation.     

Isomerization of n-butane by sulfated zirconia: the effect of calcination temperature and characterization of its surface acidity

The distributions of Brønsted and Lewis acid sites of different acid strengths on sulfated zirconia calcined at 450–650°C were measured by IR of adsorbed pyridine to elucidate the active sites for butane isomerization. The total numbers of Brønsted acid sites were largest when the catalyst was calcined at 500°C. The total numbers of Lewis acid sites increased with increasing calcination temperature to a maximum at 650°C. The catalytic activity in skeletal isomerization of butane correlated well with the number of Brønsted acid sites but not with the number of Lewis acid sites. The active sites were completely blocked by pyridine irreversibly absorbed at 350°C. We suggest that the strong Brønsted acid sites, which are able to retain pyridine against evacuation at 350°C, act as active sites for butane isomerization on sulfated zirconia.