Magnetic iron particles with high magnetization useful for immunoassay

TiO₂-encapsulated metallic Fe particles (Ti-O/Fe) were synthesized through a solid phase reaction. The Ti-O/Fe particles were non-toxic to tumor cells in a cell viability assay. After silica coating using a sol-gel method, streptavidin was covalently bound onto the Ti-O/Fe particles. Thus produced HMMI particles showed higher magnetization (114 Am²/kg) and a larger specific surface area (15 m²/g) than conventional streptavidin-immobilized magnetite particles. The high magnetization allowed for rapid magnetic separation, while the additional large specific surface area improved the detection of the adiponectin antigen both in terms of extended detection range and higher assay speed.     

Effects of polyethylenimine on morphology and property of ZnO films grown in aqueous solutions

Morphologies and properties of well-aligned ZnO films were controlled using zinc nitrate-hexamethylenetetramine aqueous solutions with the addition of polyethylenimine as a surfactant. Porous and dense ZnO films were fabricated with and without polyethylenimine, respectively. The addition of polyethylenimine proceeded to form porous ZnO whiskers film by preferential adsorption to nonpolar crystal faces and modifications of the surface free energy and growth rate. Dense ZnO film showed high transmittance of 80%, and low intensity of fluorescence and photo-induced current. Porous ZnO whiskers film showed low transmittance of 70%, while high intensity of fluorescence and high photo-induced current were detected because the porous ZnO nanowhisker film possessed a large interior surface area which can capture large amounts of DNA molecules labeled with dye molecules on the surface of ZnO crystals. High performance dye-sensitized sensors can be produced using ZnO whisker films prepared from an aqueous solution.     

Giant macrocycles composed of thiophene, acetylene, and ethylene building blocks

Fully conjugated giant macrocyclic oligothiophenes with 60pi, 90pi,120pi, 150pi, and 180pi frames (1, 2, 3, 4 and 5) have been designed, and their butyl-substituted derivatives (1a, 2a, 3a, 4a, and 5a) have been synthesized using modified Sonogashira and McMurry coupling reactions as key steps. The 60-180pi systems 1-5 are circular with 1.8-6 nm inner cavities and 3.3-7.5 nm outside molecular diameters. Compound 1a containing ten 3,4-dibutyl-2,5-thienylene, eight ethynylene, and two vinylene units has been converted into macrocyclic oligo(3,4-dibutyl-2,5-thienylene-ethynylene) 6a using bromination/dehydrobromination procedure. Giant macrocycles 1a-6a exhibit a red shift of their absorption spectra and a fairly strong fluorescence with a large Stokes shift as compared to a linear conjugated counterpart having five thiophene rings. Compounds 1a-6a exhibit multistep reversible redox behaviors with fairly low first oxidation potentials, reflecting their cyclic conjugation. Furthermore, chemical oxidation of 1a-6a with FeCl3 shows drastic changes of spectroscopic properties due to intramolecular and intermolecular pi-pi interactions. Doping of 1a-3a with iodine forms semiconductor due to its pi-donor properties and pi-pi stacking ability. X-ray analysis of 1a confirmed a round, planar structure with nanoscale inner cavity, and revealed host ability for alkanes and unique packing structure. Interestingly, 2a and 3a self-aggregate in the solid state to form "molecular wires," which are about 200 nm thick and more than 1 mm long. The internal structures of fibrous aggregates have been investigated by optical microscope, scanning electron microscopy, atomic force microscopy, and X-ray diffraction analyses.     

Laterally coupled silicon-germanium modulator for passive waveguide systems

We model a laterally coupled Franz-Keldysh add-drop ring modulator designed to overcome the C-band indirect absorption of silicon-germanium. Although our concept is based on loss-sensitive interferometry, it utilizes the same highly absorptive germanium-rich compositions geared toward complementary metal-oxide semiconductor (CMOS) photodetectors and electroabsorption modulators. The proposed device can be integrated with passive waveguide networks in which the carrier plasma modulation mechanism is ineffective. In addition, unlike previous silicon-germanium modulator schemes, complex butt-coupling between the passive transport and the active silicon-germanium waveguides is not required. Instead, the optical mode remains guided within the transport waveguide, minimizing transition losses.     

Comprehensive GMO detection using real-time PCR array: single-laboratory validation

We have developed a real-time PCR array method to comprehensively detect genetically modified (GM) organisms. In the method, genomic DNA extracted from an agricultural product is analyzed using various qualitative real-time PCR assays on a 96-well PCR plate, targeting for individual GM events, recombinant DNA (r-DNA) segments, taxon-specific DNAs, and donor organisms of the respective r-DNAs. In this article, we report the single-laboratory validation of both DNA extraction methods and component PCR assays constituting the real-time PCR array. We selected some DNA extraction methods for specified plant matrixes, i.e., maize flour, soybean flour, and ground canola seeds, then evaluated the DNA quantity, DNA fragmentation, and PCR inhibition of the resultant DNA extracts. For the component PCR assays, we evaluated the specificity and LOD. All DNA extraction methods and component PCR assays satisfied the criteria set on the basis of previous reports.     

The Effect of Reloading on Disuse Muscle Atrophy: Time Course of Hypertrophy and Regeneration Focusing on the Myofiber Cross-sectional Area and Myonuclear Change

The purpose of this study was to investigate the effect of reloading on atrophied muscle and the time course of hypertrophy and regeneration. Forty-nine male Wistar rats were randomly assigned to groups for hindlimb suspension (HS), hindlimb suspension and reloading (R), or control (C0). Rats in the HS group were suspended for 14 days. Rats in the R group were randomly divided into five subgroups for different post-hindlimb-suspension recovery times. Briefly, each subgroup was suspended for 14 days and given 1 day of reloading (R1), 3 days of reloading (R3), 7 days of reloading (R7), 10 days of reloading (R10), or 14 days of reloading (R14). Myonuclear numbers were significantly decreased in the groups with hindlimb suspension and 1 day and 3 days of reloading compared with that in the control group. We focused on the processes of change of mean myofiber cross-sectional area and myonuclear domain size; the degrees of increase of both indexes were limited until 3 days of reloading, and significantly increased after 7 days of reloading. An important finding of the current study was that the processes of muscle hypertrophy and regeneration did not show uniform change. In addition, there were differences in the ratio of increase among the stages of hypertrophy and regeneration. Therefore, consideration of the duration and method of physiotherapeutic intervention for atrophied muscle on the basis of the process of hypertrophy and regeneration is needed to provide more effective physiotherapy.     

Zinc- and indium-promoted conjugate addition-cyclization reactions of ethenetricarboxylates with propargylamines and alcohol: novel methylenepyrrolidine and methylenetetrahydrofuran syntheses

A new zinc- and indium-promoted conjugate addition-cyclization reaction to afford nitrogen- and oxygen-containing five-membered heterocycles has been developed. Reaction of ethenetricarboxylates with propargylamines (1 equiv) in the presence of ZnBr2 or InBr3 afforded methylenepyrrolidines in high yields. The stoichiometric use of ZnBr2 or InBr3 at room temperature and the catalytic use of InBr3-Et3N at 80 degrees C were effective. Reaction of ethenetricarboxylates with propargyl alcohol in the presence of ZnBr2 or InBr3 afforded methylenetetrahydrofurans.     

Asymmetric tandem Michael-aldol reactions between 3-cinnamoyloxazolidine-2-thiones and aldehydes

Reactions between chiral 3-cinnamoyl-4-methyl-5-phenyl-1,3-oxazolidine-2-thiones and aromatic aldehydes in the presence of BF3Et2O diastereoselectively produced tricyclic compounds incorporating a bridgehead carbon bound to four heteroatoms in high yields. Four stereocenters were induced during the reaction. The tricyclic products were transformed into propane-1,3-diols bearing three consecutive stereocenters by acid hydrolysis, S-methylation, and reductive removal of the chiral auxiliary.