Investigation on onset of shock-induced separation

A great number of experimental data indicating shock wave/boundary layer interactions in internal or external supersonic flows were reviewed to make clear the mechanism of the interaction and to decide the onset of shock-induced separation. The interesting conclusions were obtained for the considerably wide range of flow geometries that the onset of separation is independent of the flow geometries and the boundary layer Reynolds number. It is found that the pressure rise necessary to separate the boundary layer in supersonic external flows could be applied to such internal flows as overexpanded nozzles or diffusers. This is due to the fact that the separation phenomenon caused by shock wave/boundary layer interactions is processed through a supersonic deceleration. The shock-induced separation in almost all of interacting flow fields is governed by the concept of free interaction, and the onset of shock-induced separation is only a function of the Mach number just upstream of shock wave. However, physical scales of the produced separation are not independent of the downstream flow fields.     

A non‐repudiable negotiation protocol for security service level agreements

Security service level agreements (SSLAs) provide a systematic way for end users at home or in the office to guarantee sufficient security level when doing business or exchanging sensitive personal or organizational data with an online service. In this paper, we propose an SSLA negotiation protocol that implements non‐repudiation with cryptographic identities and digital signatures and includes features that make it resistant to denial of service attacks. The basic version of the protocol does not rely on the use of a trusted third party, and it can be used for all kinds of simple negotiations. For the negotiation about SSLAs, the protocol provides an option to use an external knowledge base that may help the user in the selection of suitable security measures. We have implemented a prototype of the system, which uses JSON Web Signature for the message exchange and made some performance tests with it. The results show that the computational effort required by the cryptographic operations of the negotiation protocol remains at a reasonable level. Copyright © 2014 John Wiley & Sons, Ltd.     

Peroxidase activity enhancement of horse cytochrome c by dimerization

The peroxidase activity of horse cytochrome c was enhanced by its dimerization, where its Compound III (oxy-form) and Compound I (oxoferryl porphyrin π-cation radical) species were detected in the reactions with hydrogen peroxide and meta-chloroperbenzoic acid, respectively. These results show that oligomeric cytochrome c can contribute as a proapoptotic conformer by the increased peroxidase activity.     

Systematic study of protein detection mechanism of self-assembling 19F NMR/MRI nanoprobes toward rational design and improved sensitivity

(19)F NMR/MRI probe is expected to be a powerful tool for selective sensing of biologically active agents owing to its high sensitivity and no background signals in live bodies. We have recently reported a unique supramolecular strategy for specific protein detection using a protein ligand-tethered self-assembling (19)F probe. This method is based on a recognition-driven disassembly of the nanoprobes, which induced a clear turn-on signal of (19)F NMR/MRI. In the present study, we conducted a systematic investigation of the relationship between structure and properties of the probe to elucidate the mechanism of this turn-on (19)F NMR sensing in detail. Newly synthesized (19)F probes showed three distinct behaviors in response to the target protein: off/on, always-on, and always-off modes. We clearly demonstrated that these differences in protein response could be explained by differences in the stability of the probe aggregates and that "moderate stability" of the aggregates produced an ideal turn-on response in protein detection. We also successfully controlled the aggregate stability by changing the hydrophobicity/hydrophilicity balance of the probes. The detailed understanding of the detection mechanism allowed us to rationally design a turn-on (19)F NMR probe with improved sensitivity, giving a higher image intensity for the target protein in (19)F MRI.     

On-chip fraction collection for multiple selected ssDNA fragments using isolated extraction channels

High efficiency and high-purity fraction collection is highly sought in analysis of fragments-of-interest from selective polymerase chain reaction (PCR) products generated by High Coverage Gene Expression Profiling (HiCEP) methods. Here we demonstrate a new electrophoretic chip device enabling automatic high-efficient fractionation of multiple ssDNA target fragments during a run of separation. We used thoroughly isolated extraction channels for each selected target to reduce the risk of cross-contamination between targets due to cross-talk of extraction channels. Fragments of 35, 108 and 138 b, were successfully isolated, then the recovery was PCR-amplified and assessed by capillary electrophoresis (CE) analysis. Total impurity level of the targets due to unwanted fragments of 0.7%, 2% and 6% respectively, was estimated. Difficulties in collecting multiple target factions are due to band diffusion and DNA adsorption to the walls for the fragments in the separation channel, which is generated by transferring the DNA target fraction from the extraction section to the target reservoir. Therefore, we have carefully measured band broadening and analyzed its influence on the separation resolution due to the delay.     

Stereochemically controlled asymmetric 1,2-reduction of enones mediated by a chiral sulfoxide moiety and a lanthanum(III) ion

Enantiomerically pure (Z)-β-sulfinyl allylic alcohols of either handedness can be readily prepared from (Z)-β-sulfinyl enones using NaBH(4) or DIBAL reductants in the presence of LaCl(3) as a chelating agent. A chiral sulfoxide auxiliary induces the remote 1,2-asymmetric reduction (1,4-induction) to afford various chiral allylic alcohols in high yields with excellent stereoselectivities (up to 100% de).     

Size-dependent inclusion of organic molecules into elastic pillared carbons

Size selective inclusion of organic molecules into pillared carbons accompanied by large interlayer expansions was observed for the first time. In order to achieve this, the distance between two adjacent pillars should be between 0.36 and 0.40 nm and they should align in the same direction.     

Electric field dependent photocurrent generation in a thin-film organic photovoltaic device with a [70]fullerene-benzodifuranone dyad

A [70]fullerene-benzodifuranone acceptor dyad synthesized by a Ag?-mediated coupling reaction was used to construct a thin-film organic solar cell. The fullerene and the benzodifuranone dye in the dyad have close-lying LUMO levels in the range of 3.7-3.9 eV, so that energy transfer from the dye to the fullerene can take place. A p-n heterojunction photovoltaic device consisting of a tetrabenzoporphyrin and a [70]fullerene-benzodifuranone dyad showed a weak but discernible contribution from light absorption of the dyad to the photocurrent under both a positive and a negative effective bias. These results indicate that the benzodifuranone moiety attached to the acceptor contributes to light-harvesting by energy transfer.     

Complex Hydrides for Electrochemical Energy Storage

Complex hydrides have energy storage‐related functions such as i) solid‐state hydrogen storage, ii) electrochemical Li storage, and iii) fast Li‐ and Na‐ionic conductions. Here, recent progress on the development of fast Li‐ionic conductors based on the complex hydrides is reported. The validity of using them as electrolytes in all‐solid‐state lithium rechargeable batteries is also examined. Not only coated oxides but also bare sulfides are found to be applicable as positive electrode active materials. Results related to fast Na‐ionic conductivity in the complex hydrides are presented. In the last section, the future prospects for battery assemblies with high‐energy densities, and Mg ion batteries with the liquid and the solid‐state electrolytes are discussed.