Examination of wet coating and co-sintering technologies for micro-SOFCs fabrication

Preparation conditions to obtain a dense electrolyte layer on a micro-tubular electrode support were investigated using wet coating and subsequent co-firing techniques. An anode-supported micro-tubular SOFC with 1.5 mm diameter was successfully fabricated by careful control of the co-sintering process of electrolyte/anode support laminates. The densification of the electrolyte layer deposited on the support surface was greatly affected by the shrinkage of tubular support during the co-sintering process. Support shrinkage above 15% was found to produce a fully densified electrolyte layer on the anode support. In contrast, the use of an anode support with shrinkage below 10% constrained gadolinium-doped ceria (GDC) sintering, resulting in a poorly densified GDC microstructure. Finally, we obtained a micro-tubular cell composed of a dense GDC and a porous (La,Sr)(Co,Fe)O₃–GDC multi-layered structure on a NiO–GDC micro-tubular anode support. The cell, with a dense and ≈15 μm thick GDC electrolyte layer, was electrochemically evaluated in a temperature range from 450 to 550 °C. This micro-tubular cell with an electrode length of 6.3 mm showed a power density above 0.1, 0.2 and 0.4 W/cm² at 450, 500 and 550 °C, respectively, in wet H₂ fuel flow.     

The reaction of propargyl alcohol with amines a novel route to aminopropanones and 2-methylquinoxaline

Propargyl alcohol reacts with a variety of amines in the presence of zinc acetate and cadmium acetate at reflux temperatures for 8–20 h to give aminopropanones in fairly good yields. o-Phenylenediamine gives 2-methylquinoxaline.     

Polymer solutions and entropic-based systems for double-stranded DNA capillary electrophoresis and microchip electrophoresis

We give an overview of recent development of low-viscosity polymer solutions and entropic trapping networks for double-stranded DNA (dsDNA) separations by conventional capillary electrophoresis and microchip electrophoresis. Theoretical models for describing separation mechanisms, commonly used noncross-linked polymer solutions, thermoresponsive (viscosity-adjustable) polymer solutions, and novel entropic trapping networks are included. The thermoresponsive polymer solutions can be loaded at one temperature into microchannels at lower viscosities, and used in separation at another temperature at entanglement threshold concentrations and higher viscosities. The entropic-based separations use only arrays of regular obstacles acting as size-separations and do not need viscous polymer solutions. These progresses have potential in integration to automated capillary and microfluidic chip systems, enabling better reusability of separation microchannels, much shorter DNA separation times, and higher reproducibility due to less matrix degradation.     

On-chip fabrication of mutifunctional envelope-type nanodevices for gene delivery

Microfluidic devices may be highly beneficial to the rapid fabrication of small quantities of various nonviral vectors with different functionalities, which is indispensable for effective order-made gene therapy. We adapted a microfluidic chip-based approach for fabricating small quantities of nonviral vectors in a short time in preparation for order-made gene therapy applications. This approach permitted us to fabricate multifunctional envelope-type nanodevices (MENDs), composed of a compacted (or condensed) DNA core and a lipid bilayer membrane shell, which are considered as promising nonviral vectors for gene therapy applications. The on-chip fabrication of the MEND was very simple, rapid, convenient, and cost-effective compared with conventional methods. The size of the MEND showed strong dependence on the concentration and flow rate of the reaction precursors and could be controlled to be much smaller than that achievable by conventional methods. This, together with abovementioned merits, makes our microfluidic chip-based approach very attractive for the fabrication of MENDs for effective application to order-made gene therapy.     

Determination of human blood glucose levels using microchip electrophoresis

A high-performance monitoring system for human blood glucose levels was developed using microchip electrophoresis with a plastic chip. The combination of reductive amination as glucose labeling with fluorescent 2-aminoacridone (AMAC) and glucose-borate complex formation realized the highly selective detection of glucose even in a complex matrix such as a blood sample. The migration time of a single peak, observed on an electropherogram of AMAC-labeled plasma, closely resembled that of glucose standard solution. The treatment of plasma with hexokinase or glucokinase for glucose phosphorylation resulted in a peak shift from approximately 145 to 70 s, corresponding to glucose and glucose-6-phosphate, respectively. A double-logarithm plot revealed a linear relationship between glucose concentration and fluorescence intensity in the range of 1-300 microM of glucose (r(2) = 0.9963; p <0.01), and the detection limit was 0.92 microM. Furthermore, blood glucose concentrations estimated from the standard curves of three subjects were compared with results obtained by conventional colorimetric analysis using glucose dehydrogenase. Good correlation was observed between methods according to simple linear regression analysis (p <0.05). The reproducibility of the assay was about 6.3-9.1% (RSD) and the within-days and between-days reproducibility were 1.6-8.4 and 5.2-7.2%, respectively. This system enables us to determine blood glucose with high sensitivity and accuracy, and will be applicable to clinical diagnosis.     

First chemical synthesis of antioxidative metabolites of sesamin

The first chemical synthesis of two metabolites ((1R,2S,5R,6S)-6-(3,4-dihydroxyphenyl)-2-(3,4-methylenedioxyphenyl)-3,7-dioxabicyclo[3,3,0]octane (SC-1) and (1R,2S,5R,6S)-2,6-bis(3,4-dihydroxyphenyl)-3,7-dioxabicyclo[3,3,0]octane (SC-2)) of sesamin was achieved by a simple two-step approach from sesamin. The approach consists of acetoxylation of the methylenedioxy moiety(ies) with lead(IV) tetraacetate and acid hydrolysis of the resulting hemiorthoester to SC-1 and SC-2.     

First isolation of 1,2-dithietan-3-one from α-dithiolactone

Treatment of α-dithiolactone 6 with ethoxycarbonylformonitrile oxide 7 resulted in the formation of 1,2-dithietan-3-one 4. Compound 4a was oxidized with m-CPBA to give 4,4-di-tert-butyl-1,2-dithietan-3-one 1-oxide 5a. The reaction of 4a with triphenylphosphine afforded the corresponding α-thiolactone 10.     

Highly sensitive double-fluorescent dye staining on microchip electrophoresis for analysis of milk proteins

We demonstrated a highly sensitive double-fluorescent dye staining in microchip electrophoresis (ME) for analysis of milk proteins. The detection sensitivity of ME was very limited so far and needed improvement. Our staining method consisted of two steps. First, in sample preparation before electrophoresis, protein was covalently bound to an amine-reactive fluorescent dye, Cy5. Then, the Cy5-attached protein was denatured with SDS and was further stained, during electrophoresis, with Agilent fluorescent dye, which was noncovalently attached to hydrophobic regions of the SDS-protein complexes. This double-fluorescent staining enhanced fluorescent intensity and lowered the detection limit to 200 pg of protein. This provided higher sensitivity than silver- or SYPRO Ruby-staining methods, which have previously given the highest sensitivity in protein staining. In addition, we applied our staining method to analysis of milk proteins and achieved their successful detection, whereas it was difficult to analyze them by the unimproved method.