Conversion of chemical into mechanical energy by contractile polymers performed by polymer complexation

A mechanochemical energy conversion system working upon polymer-polymer complexation between poly(methacrylic acid) (PMAA) and poly(ethylene glycol) (PEG) was studied. It was found that among PEGs of various molecular weights used, PEG with molecular weight of 2000 provided the most rapid and significant contraction of crosslinked PMAA membrane loaded 100 times the weight of dry membrane, exhibiting about 2000 g/cm² of stress. Increasing and decreasing the molecular weight of PEG from 2000 brought about gradual decrease both in the contraction and stress of the membrane. The work done per contraction per gramme of contractile substance was studied for various loads. It was found that the work done increased linearly with increasing weight of load, reaching 200 g cm.     

Peptide Nucleic Acid Conjugated with Ruthenium‐Complex Stabilizing Double‐Duplex Invasion Complex Even under Physiological Conditions

Peptide nucleic acid (PNA) can form a stable duplex with DNA, and, accordingly, directly recognize double‐stranded DNA through the formation of a double‐duplex invasion complex, wherein a pair of complementary PNA strands form two PNA/DNA duplexes. Because invasion does not require prior denaturation of DNA, PNA holds great potential for in cellulo or in vivo applications. To broaden the applicability of PNA invasion, we developed a new conjugate of PNA with a ruthenium complex. This Ru–PNA conjugate exhibits higher DNA‐binding affinity, which results in enhanced invasion efficiency, even under physiological conditions.     

Process intensification using a two‐phase system and micromixing for consecutive and reversible reactions

This study aimed to find reaction conditions that improve the yield of target intermediate products, using a two‐phase system and a microspace for first‐order consecutive and reversible reactions. As a result, the yield of target products with a two‐phase system can be surpassed by that of a single‐phase system through selecting the organic phase such that the partition coefficient of the raw material to the aqueous phase is large, and that of the target product to the organic phase is also large. In addition, the volume ratio of two phases and the liquid–liquid interfacial area are also important factors for improving the target product yield. In a microspace, the microfluid segments can be designed both arbitrarily and precisely, and thus it is possible to control the interfacial area and mass transfer rates accurately. Utilization of a microspace can play a significant role in intensifying a two‐phase system. © 2009 American Institute of Chemical Engineers AIChE J, 2009     

Physical and electrochemical properties of room-temperature dicyanamide ionic liquids based on quaternary phosphonium cations

The physicochemical and electrochemical properties of room temperature ionic liquids based on quaternary phosphonium cations together with a dicyanamide anion are presented in this report. The most dicyanamide-based phosphonium ionic liquids prepared were hydrophilic, except ionic liquids containing a long alkyl chain in the phosohonium cation. It was found that asymmetric phosphonium cations gave low-melting salts in combination with a dicyanamide anion. The dicyanamide-based phosphonium ionic liquids exhibited relatively low viscosities and high conductivities when compared to those of the corresponding ammonium ionic liquids. Particularly, the ionic liquids containing a methoxy group in the phosphonium cations indicated very low viscosities. Comparatively good electrochemical stability of the dicyanamide-based phosphonium ionic liquids was confirmed by voltammetric measurements. The thermogravimetric analysis suggested that the dicyanamide-based phosphonium ionic liquids showed higher thermal stability than those of the corresponding ammonium ionic liquids, indicating an improving effect of the phosphonium cations on the thermal stability.     

Conduction-corrected modified effective temperature as the indices of combined and separate effect of environmental factors on sensational temperature

In living spaces, people sit or lie on the floor and adopt a posture in which much of the surface of the body is in contact with the floor. When the temperature of the spatial structure or the surface temperature of an object in contact with the human body is not equivalent to the air temperature, these effects are non-negligible. Most research examining the physiological and psychological responses of the human body has involved subjects sitting in chairs. Research that takes into account body heat balance and assessments of thermal conduction into the environment is uncommon. Thus, in this study, conduction-corrected modified effective temperature (ETF), which is a new thermal environmental index incorporating heat conduction, is defined in order to make possible the evaluation of thermal environments that take into account different postures. This sensational temperature index converts the effects of the following parameters into a temperature equivalent: air velocity, thermal radiation, contact material surface temperature and humidity. This index has the features of a summation formula. Through the use of these parameters, it is possible to represent and quantify their composite influence on bodily sensation and the effects of discrete meteorological elements through an evaluation on an identical axis.     

Single-Step Reconstitution of Apo-Hemoproteins at the Disruption Stage of Escherichia coli Cells

Hemoproteins on their metal: We report a novel strategy for the reconstitution of hemoproteins with non-natural metal complexes; simple addition of manganese and ruthenium porphyrin to E. coli cells immediately prior to homogenization yields the reconstituted proteins. We believe that this simple approach could become a standard reconstitution method for hemoproteins.     

Gel biomachine based on muscle proteins

Summary We have created an ATP-fueled soft gel machine constructed from muscle proteins. Chemically cross-linked gels of the polymer-actin complex of the length several decades times the length of native actin filament (F-actin) move on myosin-coated surface with a velocity as high as that of native F-actin, by coupling to ATP hydrolysis. The motility observed in muscle protein-gels suggests that one might construct a soft machine fueled by chemical energy using actin and myosin molecules as elements. We have investigated the growth process of polymer-actin complexes and the correlation between the polarity and the motility of polymer-actin complex gels.     

Radiation degradation of large fluence irradiated space silicon solar cells

In this paper, we present data on the electrical properties of 50 gm thick space silicon BSFR cells irradiated with 10 MeV protons with a fluence exceeding 1 x 10¹³ p/cm² and irradiated with 1 MeV electrons with a fluence exceeding 1 x 10¹⁶ e/cm², and discuss the anomalous degradation which was found in these large-fluence regions. These data show an increase of saturation current density and a decrease of diffusion voltage of the pn junction, and a decrease of majority carrier density and an increase of series resistance of the p-substrate as a result of the formation of a large amount of carrier traps by the large-fluence irradiation.