Compact disk (CD)-shaped device for single cell isolation and PCR of a specific gene in the isolated cell

For immediate discrimination among isolated cells we propose a novel device and technique for isolation of cells and sequential detection of specific gene(s) within them by polymerase chain reaction (PCR). In this study, we isolated Salmonella enterica cells and detected the Salmonella-specific invA gene from isolated cells by PCR on a compact disk (CD)-shaped device. This device enabled liquid flow by centrifugal force without a micro pump, and was fabricated from silicon wafer and glass to avoid evaporation of a small amount of reagent. One device has 24 microchannels, and 313 microchambers integrated on each microchannel. One microliter of PCR mixture containing cells was separated into microchambers on the device at 5000 rpm for 30 s. Each microchamber contained approximately 1.5 nL PCR mixture. A Poisson distribution of S. enterica cells was observed for different densities of cell suspension. At 200 cells μL^?1 of S. enterica or less, isolated single cells could be determined on the device by amplification of DNA of the invA gene; at 400 cells μL^?1, chambers containing no, one, two, or three cells could be determined on the device. Selective detection of S. enterica was achieved by PCR from a mixture of S. enterica and Esherichia coli on the CD-shaped device.     

An optimal design method for preventing air bubbles in high-temperature microfluidic devices

DNA analysis with the polymerase chain reaction (PCR) has become a routine part of medical diagnostics, environmental inspections, food evaluations, and biological studies. Furthermore, the development of a microscale PCR chip is an essential component of studies aimed at integrating PCR into a micro total analysis system (μ-TAS). However, the occurrence of air bubbles in microchannels complicates this process. In this study, we investigated a new technique based on the fluid dynamics of laminar flow that utilizes a small amount of mineral oil at the beginning of sample injection to prevent air bubbles from occurring in microchannels. We also further optimized the pressure, the length of the pressurizing channel and the volume of oil, thus making our microfluidic device more useful for high-temperature PCR. Additionally, quantitative continuous-flow PCR was performed using the optimized PCR chip in order to detect genetically modified (GM) maize. DNA was extracted from GM maize, MON 810, and non-GM maize at several concentrations from 0% (w/v) to 100% (w/v). The DNA amplification signals were then analyzed on the PCR chip using a laser-based system. The signal from our microfluidic PCR chip was found to increase in direct proportion to the initial GM maize concentration.     

Structure elucidation of a novel analog of sildenafil detected as an adulterant in a dietary supplement using LC-UV and LC/MS

A sildenafil-related compound was detected in a dietary supplement marketed as an aphrodisiac. The compound was detected during analysis of the dietary supplement using LC-UV and LC/electrospray ionization-MS. The structure of the compound was established using high resolution MS, NMR spectrometry, and X-ray crystal structure analysis. The compound was identified as 5-(5-((3,5-dimethylpiperazin-1-yl)sulfonyl)-2-ethoxyphenyl)-l-methyl-7-((1-methyl-4-nitro-1H-imidazol-5-yl)thio)-3-propyl-1H-pyrazolo[4,3-d] pyrimidine. Based on this structure, the compound was named nitroprodenafil. The dietary supplement was found to contain 90 mg nitroprodenafil/capsule. This article describes the structural characterization of a new sildenafil-related compound. The compound was detected during analysis of a dietary supplement using LC-UV and LC/electrospray ionization (ESI)-MS. The structure was established using high resolution MS (HRMS), NMR spectrometry, and X-ray crystal structure analysis. The structures of methisosildenafil, thiomethisosildenafil, and this new analog, named nitroprodenafil (21), are shown in Figure 1. In the Demizu et al. report, the compound is named mutaprodenafil instead ofnitroprodenafil. Considering the naming right, the authors of this paper think the use of mutaprodenafil is appropriate as the compound name, although nitroprodenafil is used.     

Stereoselective construction of the octalin unit of symbioimine using an intramolecular Diels-Alder reaction

The octalin unit of symbioimine (1) has been synthesized stereoselectively via an intramolecular Diels-Alder reaction.     

A novel enhancement assay for immunochromatographic test strips using gold nanoparticles

The immunochromatographic assay is a well-known and convenient diagnostic system. In this report, the development of a novel enhancement assay for the test strips is described. Additionally, this highly sensitive immunochromatographic assay was applied to detect human chorionic gonadotropin hormone (HCG) as the model case. The primary antibody-conjugated gold nanoparticles were used as the enhancer of the standard method. The primary antibodies were immobilized within a defined detection zone (test line) on the diagnostic nitrocellulose membrane. The secondary antibodies were conjugated with colloidal gold nanoparticles. In combination with an effective sample pretreatment, the gold-conjugated antibodies and the primary antibodies formed a sandwich complex with the target protein. Within the test line, the sandwich complex was immobilized, and furthermore, concentrated by the enhancer resulting in a localized surface plasmon resonance (LSPR) phenomenon and a distinct red color on the test line. The intensity of color of the red test line (signal intensity), which correlated directly with the concentration of the target protein in the standard or spiked samples, was assessed visually and by computer image analysis using a three-determination analysis. Under optimum conditions, the limit of detection (LOD) for HCG assay was 1 pg/mL. When using human serum, 10 pg/mL of HCG could be detected. We have also spiked total prostate-specific antigen (TPSA) in female serum. The LOD for TPSA was determined as 0.2 ng/mL. With this method, the quantitative determination of the target protein could be completed in less than 15 min. Our novel immunochromatographic strips using the enhancing method based on LSPR of gold nanoparticles are useful as a rapid and simple screening method for the detection of important analytes for medical applications, environmental monitoring, food control, and biosecurity.      

Intermittent Structures in the High Field Side Boundary of the HYBTOK-II Tokamak

The spatial and temporal characteristics of the turbulence in the inboard and outboard scrape-off layer (SOL) of tokamak HYBTOK-II have been studied using poloidal probe array. Bursty behaviour with intermittent bursts was observed for both outboard and inboard SOL. In the inboard (high field side), high level of density fluctuations has been observed. The fluctuations in the high field side and low field side are identical in statistics that is non-Gaussian one.     

Metabolic profiling of urine and blood plasma in rat models of drug addiction on the basis of morphine,methamphetamine, and cocaine-induced conditioned place preference

The metabolic profiles of urine and blood plasma in drug-addicted rat models based on morphine (MOR), methamphetamine (MA), and cocaine (COC)-induced conditioned place preference (CPP) were investigated. Rewarding effects induced by each drug were assessed by use of the CPP model. A mass spectrometry (MS)-based metabolomics approach was applied to urine and plasma of MOR, MA, and COC-addicted rats. In total, 57 metabolites in plasma and 70 metabolites in urine were identified by gas chromatography–MS. The metabolomics approach revealed that amounts of some metabolites, including tricarboxylic acid cycle intermediates, significantly changed in the urine of MOR-addicted rats. This result indicated that disruption of energy metabolism is deeply relevant to MOR addiction. In addition, 3-hydroxybutyric acid, l-tryptophan, cystine, and n-propylamine levels were significantly changed in the plasma of MOR-addicted rats. Lactose, spermidine, and stearic acid levels were significantly changed in the urine of MA-addicted rats. Threonine, cystine, and spermidine levels were significantly increased in the plasma of COC-addicted rats. In conclusion, differences in the metabolic profiles were suggestive of different biological states of MOR, MA, and COC addiction; these may be attributed to the different actions of the drugs on the brain reward circuitry and the resulting adaptation. In addition, the results showed possibility of predict the extent of MOR addiction by metabolic profiling. This is the first study to apply metabolomics to CPP models of drug addiction, and we demonstrated that metabolomics can be a multilateral approach to investigating the mechanism of drug addiction.     

A photoactivated artificial muscle model unit: reversible, photoinduced sliding of nanosheets

A novel photoactivated artificial muscle model unit is reported. Here we show that organic/inorganic hybrid nanosheets reversibly slide horizontally on a giant scale and the interlayer spaces in the layered hybrid structure shrink and expand vertically by photoirradiation. The sliding movement of the system on a giant scale is the first example of an artificial muscle model unit having much similarity with that in natural muscle fibrils. In particular, our layered hybrid molecular system exhibits a macroscopic morphological change on a giant scale (~1500 nm) relative to the molecular size of ~1 nm by means of a reversible sliding mechanism.     

Recovery of electrical resistivity in amorphous pdsi alloys after low temperature neutron irradiation

Measurements of electrical resistivity after low temperature fast neutron irradiation are made for amorphous Pd₈₀Si₂₀ and Pd₈₀Ni₂Sl₁₈ and then Pd₈₀Si₂₀ annealed at 230°C and 360°C, and the isochronal annealing curves are obtained. The resistivity increase of Pd₈₀Si₂₀ annealed at 360°C is about 10 times larger than that of amorphous alloys and no defined annealing stage is observed in amorphous alloys and Pd₈₀Si₂₀ annealed at 360°C. For amorphous Pd₈₀Si₂₀, about 60% of the resistivity increase by irradiation remains after annealing up to room temperature and these are discussed by the structural relaxation.