Morphology of Polystyrene Core–dPoly(ethylene oxide) Shell Arborescent Copolymer Micelles from Small-Angle Neutron Scattering Analysis

Arborescent (dendrigraft) copolymers with a branched polystyrene (PS) core grafted at the chain termini with deuterated poly(ethylene oxide) segments (PS-dPEO) were characterized in benzene and acetone by small-angle neutron scattering measurements using the contrast matching technique. While copolymers incorporating a G1 (twice-grafted) PS core aggregated to some extent, the portion of the scattering curve corresponding to non-aggregated copolymer molecules could still be analyzed to determine the shape and segment radial density profile for core and shell. These were derived from the pair distance distribution function P(r) and the scattering length density contrast profile Δρ(r) = ρ(r) ? ρ(solvent), obtained by the indirect Fourier transformation and deconvolution methods. The profiles obtained for the G1 copolymer are consistent with a well-defined PS core–dPEO shell morphology, only observed previously for upper generation (G4) polymers with deuterated PS (dPS) chains grafted randomly on arborescent PS substrates. Detailed morphological analysis could not be carried out for an analogous G3 arborescent PS copolymer terminally grafted with dPEO segments due to extensive aggregation in both solvents.     

Heritability and linkage study on heart rates in a Mongolian population

Elevated heart rate has been proposed as an independent risk factor for cardiovascular diseases, but their interrelationships are not well understood. In this study, we performed a genome-wide linkage scan in 1,026 individuals (mean age 30.6 years, 54.5% women) from 73 extended families of Mongolia and determined quantitative trait loci that influence heart rate. The DNA samples were genotyped using deCODE 1,039 microsatellite markers for 3 cM density genome-wide linkage scan. Correlation analysis was carried out to evaluate the correlation of the covariates and the heart rate. T-tests of the heart rate were also performed on sex, smoking and alcohol intake. Consequently, this model was used in a nonparametric genome-wide linkage analysis using variance component model to create a multipoint logarithm of odds (LOD) score and a corresponding P value. In the adjusted model, the heritability of heart rate was estimated as 0.32 (P<.0001) and a maximum multipoint LOD score of 2.03 was observed in 77 cM region at chromosome 18. The second largest LOD score of 1.52 was seen on chromosome 5 at 216 cM. Genes located on the specified locations in chromosomes 5 and 18 may be involved in the regulation of heart rate.     

Co-localization and interaction of human organic anion transporter 4 with caveolin-1 in primary cultured human placental trophoblasts

The human organic anion transporter 4 (hOAT4) has been identified as the fourth isoform of OAT family. hOAT4 contributes to move several negatively charged organic compounds between cells and their extracellular milieu. The functional characteristics and regulatory mechanisms of hOAT4 remain to be elucidated. It is well known that caveolin plays a role in modulating proteins having some biological functions. To address this issue, we investigated the co-localization and interaction between hOAT4 and caveolin-1. hOAT4 and caveolin-1 (mRNA and protein expression) were observed in cultured human placental trophoblasts isolated from placenta. The confocal microscopy of immuno-cytochemistry using primary cultured human trophoblasts showed hOAT4 and caveolin-1 were co-localized at the plasma membrane of the cell. This finding was confirmed by Western blot analysis using isolated caveolae-enriched membrane fractions and immune-precipitates from the trophoblasts. When synthesized cRNA of hOAT4 along with scrambled- or antisense-oligodeoxynucleotide (ODN) of Xenopus caveolin-1 were co-injected to Xenopus oocytes, the [3H]estrone sulfate uptake was significantly decreased by the co-injection of antisense ODN but not by scrambled ODN. These findings suggest that hOAT4 and caveolin-1 share a cellular expression in the plasma membrane and caveolin-1 up-regulates the organic anionic compound uptake by hOAT4 under the normal physiological condition.     

Expression of hepatitis C virus nonstructural 4B in transgenic mice

Hepatitis C virus (HCV) is a pathogen that is of great medical significance in chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma worldwide. Although the HCV proteins have been intensively investigated over the past decade, the biochemical functions of the NS4B protein are still largely unknown. To investigate NS4B as a potential causative agent of liver disease, transgenic mice expressing the NS4B protein in liver tissue were produced. The transgenic animals were phenotypically similar to their normal littermates for up to 18 months of age. Our results suggest that the HCV NS4B protein is not directly cytopathic or oncogenic in our transgenic mice model.     

Self-induced 1-D molecular chain growth of thiophene on Ge(100)

The adsorption of thiophene on Ge(100) has been studied using scanning tunneling microscopy (STM), high-resolution core-level photoemission spectroscopy (HRPES), and density functional theory (DFT) calculations. Until now, thiophene is known to react with the Ge(100) dimer through a [4 + 2] cycloaddition reaction at room temperature, similar to the case of thiophene on Si(100). However, we found that thiophene has two adsorption geometries on Ge(100) at room temperature, such as a kinetically favorable Ge-S dative bonding configuration and a thermodynamically stable [4 + 2] cycloaddition adduct. Moreover, our STM results show that under 0.25 ML thiophene molecules preferentially produce one-dimensional molecular chain structures on Ge(100) via the Ge-S dative bonding configuration.     

A highly selective chemodosimeter for the rapid detection of Hg2+ ions in aqueous media

A novel S,S′-diallyl carbohydrazonodithioate derivative 3 of rhodamine B hydrazone was developed as a chemodosimeter for selective detection of mercury ions based on Hg²⁺ promoted cyclization. The allyl groups of 3 play a key role in the binding and selection of Hg²⁺ ions. The probe responds selectively to Hg²⁺ over various other competitive cations with marked chromo- and fluorogenic changes. The formation of stable oxadiazole derivative 8 was a strong driving force for this high selectivity. Practically, this probe is more promising because of the remarkable high selectivity, faster response, low detection limit, and aqueous solubility of 3.     

A metal-free C–C/C–O bond formation for the synthesis of 2-amino-5-oxo-4-aryl-4H,5H-pyrano[3,2-c]chromene-3-carboxamide catalyzed by polystyrene-supported p-toluenesulfonic acid (PS-PTSA)

An efficient and eco-friendly procedure for the synthesis of 2-amino-5-oxo-4-aryl-4H,5H-pyrano[3,2-c]chromene-3-carboxamide has been developed through a one-pot three-component condensation of 4-hydroxycoumarin with aldehydes and cyanoacetamide, in the presence of catalytic amount of polystyrene-supported p-toluenesulfonic acid (PS-PTSA) as a highly active and reusable heterogeneous acid catalyst in EtOH at 80?°C conditions. This new procedure offers several advantages such as shorter reaction times, excellent yields, a wide range of functional group tolerance, easy experimental work-up procedure, operationally simple under metal-free reaction conditions and C-C/C-O bond formation. The catalyst can be recovered and reused for at least four runs without any significant impact on the product yields.     

Precise determination of lithium isotopes in seawater using MC-ICP-MS

Li (lithium) isotope analysis using MC-ICP-MS is a very powerful tracer measurement method. This is widely used for identification of Li isotopes in many fields of study. This useful method, however, has an effect on the natural Li isotope background. This is impacted by the instrument matrix. In this study, we show that the MC-ICP-MS condition is characterized by both a low baseline background and a high-sensitivity distance at Ar plasma condition. In addition, the Li isotope ratio was measured by the use of experimental conditions that were superior to both the general plasma condition and those used in other studies. The samples were subjected to both acid leaching and a cation exchange resin (Bio-Rad AG 50 W-X8 200–400 mesh) modified for seawater samples. The isotope variations were corrected using the bracket method, the measured Li isotope ratio of sample, and the mean ratios of the L-SVEC standard (NIST L-SVEC Li₂CO₃) measured before and after the sample run. The isotope variation was presented as the deviation (per mil) of the measured ratio from that of the recommended value.     

Investigation of Rotating Arc-Catalytic Reactor for CF4 Removal with High Energy Efficiency

Plasma Chemistry and Plasma Processing - CF4 is commonly used in semiconductor industries, and its removal requires a large amount of energy because it is a highly stable perfluorinated compound....