Integration of multianalyte sensing functions on a capillary-assembled microchip: simultaneous determination of ion concentrations and enzymatic activities by a "drop-and-sip" technique

A general and simple implementation of simultaneous multiparametric sensing in a single microchip is presented by using a capillary-assembled microchip (CAs-CHIP) integrated with the plural different reagent-release capillaries (RRCs), acting as various biochemical sensors. A novel "drop-and-sip" technique of fluid handling is performed with a microliter droplet of a model sample solution containing proteases (trypsin, chymotrypsin, thrombin, elastase) and divalent cations (Ca2+, Zn2+, Mg2+) that passes through the microchannel with the aid of a micropipette as a vacuum pump, concurrently filling each RRC via capillary force. To avert the evaporation of the nanoliter sample volume in each capillary, PDMS oil is dropped on the outlet hole of the CAs-CHIP exploiting the capillary force that results in spontaneous sealing of all the RRCs. In addition, this high-speed sample introduction alleviates the possibility of protein adsorption and capillary cross-contamination, allowing a reliable and multianalyte determination of a sample containing many different proteases and divalent cations by using the fluorescence image analysis. Presented results suggested the possible application of this microchip in the field of drug discovery and systems biology.     

Visualization technique for time-variant hydrogen concentration distribution in porous materials using hydrogen storage alloy thin film

An understanding of the mechanism whereby hydrogen is transported in porous materials is a key factor when developing hydrogen-utilizing equipment. For instance, studying the start-up and degradation characteristics of Polymer Electrolyte Fuel Cell (PEFC) requires the distribution of the time-variant hydrogen concentration to be measured at times of the order of 10^?1 s. However, few studies on time-variant hydrogen transport in porous materials have been reported, and conventional measuring methods are insufficient in terms of their time resolution. This study led to the development of a visualization technique using the characteristics of a MgNi thin film, the reflection rate of which changes along with the hydrogen concentration. The new visualization technique makes it possible to investigate and understand the distribution of the time-variant hydrogen concentration.     

SEM observation of wet biological specimens pretreated with room-temperature ionic liquid

A facile pretreatment process for SEM: The use of room temperature ionic liquids (RTILs) provides an interesting method for SEM of biological specimens. We used a novel and concise method of pretreatment, excluding fixation or Au sputtering steps. Fine and smooth-textured SEM images of a wide variety of biological specimens treated in this way were observed without artefacts.     

A 31P-NMR study of peroxo species formed during oxidation of cyclohexene with hydrogen peroxide in tri-n-butylphosphate catalyzed by heteropolyacids

In the oxidation of cyclohexene with H₂O₂in monophasic tri-n-butylphosphate (TBP) solution catalyzed by Keggin-type 12-heteropolyacids, i.e., H₃PMo_12-xW _x O₄₀(x=0–12), several peroxo species were observed by ³¹P-NMR spectroscopy in lower field than the original heteropolyacids. Their composition varied regularly with that of the starting catalyst. The P-containing peroxo species formed was deduced as [PM₄O₈(O₂)₈]^3-(M = Mo, W). The peroxo species formed more easily with a decrease in the W content, x of H₃PMo_12-xW_xO₄₀. It was further indicated from the reactivity with cyclohexene and the comparison with catalytic performance that W-rich peroxo species were catalytically more active than Mo-rich peroxo species for the oxidation of cyclohexene in this reaction system.     

Investigation of soil deformation characteristics during pullout of a ribbed reinforcement using X-ray micro CT

Steel-strip reinforced earth walls stabilize through the pullout resistance of the reinforcements. Soil dilation during the pullout of ribbed reinforcements may contribute to the evolution of pullout resistance; however, few studies have clarified this mechanism by investigating how soils behave with increasing pullout displacement. The ribs of the reinforcements enhance the pullout resistance, although the influence of the rib dimensions on the evolution of pullout resistance with increasing pullout displacement has not been sufficiently revealed. In the present study, a triaxial pullout apparatus is developed and pullout tests are conducted using ribbed reinforcements with different rib-inclination angles under isotropic stress. The displacement and strain fields in the soils during the pullout of the reinforcements are investigated by X-ray micro CT and a digital image correlation technique. It is found that larger rib-inclination angles provide higher pullout resistance at an early stage of the pullout because of the higher bearing resistance related to the more significant soil densification above the ribs. With increasing pullout displacement, the reinforcements with different rib-inclination angles come to behave as almost one in the same since a rigid soil wedge related to the passive soil failure is generated above the ribs. This tendency results in similar soil deformation characteristics and pullout resistance levels for every reinforcement beyond the soil failure state, although the rib-inclination angles are different.     

Preparation of microporous membranes from cation exchange membranes prepared by the paste method

A microporous membrane is prepared by treating the cation exchange membrane (Fe⁺⁺⁺ form) with an H₂O₂ aqueous solution. The cation exchange membrane is prepared by the paste method: the base membrane is prepared beforehand and then sulfonated. The preparative conditions of the base membrane were studied in connection with the characteristics of the resultant microporous membrane. Furthermore, the availability of the microporous membrane for ultrafiltration was studied by using an aqueous solution of a bovine hemoglobin.     

3Beta-hydroxysteroid dehydrogenase activity in human osteoblast-like cells

In spite of improvements in single or double lung transplantation (LT) technique, complications after LT are not uncommon; the most frequent ale anastomotic complications, infections and rejection (acute or chronic). Early detection of complications of LT allows the optimal therapeutic option to be taken, yielding decreased morbidity and mortality. In some cases, CT plays a key role in early detection of several complications of LT that may not be depicted with other diagnostic modalities, so that knowledge of their CT features is important. In this pictorial review, the authors describe the spectrum of CT features of the complications of LT (including reimplantation response, mechanical problems, acute and chronic rejection, infection, lymphoproliferative disorders, recurrence of the initial disease and complications involving the pleura and the anastomotic sites). In addition, the authors analyze the value of CT compared to that of the other available modalities for the detection of complications of LT.     

Probabilistic reconstruction of ancestral protein sequences

Using a maximum-likelihood formalism, we have developed a method with which to reconstruct the sequences of ancestral proteins. Our approach allows the calculation of not only the most probable ancestral sequence but also of the probability of any amino acid at any given node in the evolutionary tree. Because we consider evolution on the amino acid level, we are better able to include effects of evolutionary pressure and take advantage of structural information about the protein through the use of mutation matrices that depend on secondary structure and surface accessibility. The computational complexity of this method scales linearly with the number of homologous proteins used to reconstruct the ancestral sequence.     

Reaction of Silane with Atomic Oxygen at High Temperatures

The reaction of silane with atomic oxygen (³P) was investigated by the shock-tube–laser-photolysis method over the temperature range of 900–1170 K. Oxygen atoms were produced by the ArF laser photolysis of SO₂ behind reflected shock waves and monitored with atomic resonance absorption spectroscopy. The rate constant for the SiH₄ + O reaction was evaluated by taking the possible contribution of the consecutive reaction into consideration. The Arrhenius temperature coefficient was determined to be E_a= 26.6 kJ mol⁻¹, which is much higher than the experimental activation energies obtained at lower temperatures. Rate constants calculated by a transition state theory with the reaction barrier height of E₀= 10.2 kJ mol⁻¹ agreed well with both the present and the previous experimental results for a wide temperature range.     

In Situ Time-Resolved XAFS of Transitional States of Pt/C Cathode Electrocatalyst in an MEA During PEFC Loading with Transient Voltages

The transitional states of a Pt/C cathode electrocatalyst in the membrane electrode assembly of a polymer electrolyte fuel cell during loading with transient voltages were systematically analyzed by in situ time-resolved X-ray absorption fine structure with time resolution of 100 ms. The results suggest that the local coordination of the Pt cathode electrocatalyst was unaffected by the transient voltages during both rapid and gradual loading over 0–30 s.