γ-Radiolysis of benzophenone aqueous solution at elevated temperatures up to supercritical condition

A product analysis study of γ-irradiated benzophenone aqueous solutions from room temperature to 400 °C has been carried out by the combination of a flow irradiation system and a liquid chromatographic method. At room temperature, the main decomposition products are phenol and hydroxybenzophenone isomers. In high temperature and supercritical water solutions, 9-fluorenone appears as an important product and the G-value of benzophenone consumption depends significantly on the water density under supercritical conditions.     

Preparation and characterization of AgI nanoparticles with controlled size,morphology and crystal structure

AgI nanoparticles were prepared by solution-based routes using water-soluble anionic or cationic polyelectrolytes as capping agents. Depending on the polyelectrolytes, AgI nanoparticles with well-defined morphology, size, and phase compositions were obtained: the use of poly(sodium 4-styrenesulfonate) (PSS) resulted in AgI nano-rods of β-AgI in wurtzite structure (2H); with poly(acrylic acid sodium salt) (PAS) truncated-tetrahedron shaped γ-AgI nanoparticles (nanotetrahedra) in zinc-blende structure (3C) were obtained; by employing poly(diallyldimethylammonium chloride) (PDADMAC) plate-like AgI nanoparticles (nano-plates) consisting of unusual polytype phases of AgI (7H and 9R) were formed. Macroscopically unstable γ-AgI and 7H and 9R phases could be stabilized in the form of nanocrystalline powders. They transform reversibly into the high temperature α-AgI phase and exhibit unusually high ionic conductivity and substantially smaller transformation enthalpy values compared to the macroscopic β-AgI.     

A numerical investigation of the resonance of gas-filled microbubbles: resonance dependence on acoustic pressure amplitude

The general Keller–Herring equation for free gas bubbles is augmented by specific terms to describe the elasticity, viscosity and thickness of the encapsulating shell in ultrasound contrast agent microbubbles. A numerical investigation that analyses the acoustic backscatter from bubbles is employed to identify resonance frequencies that can be compared, for increasing driving pressure amplitude, with linear approximations obtained via analytical considerations. Calculations for bubbles of the size employed in diagnostic ultrasound, between 2 and 6 μm diameter, that are immersed in water and blood and exposed to monochromatic insonation, causing the bubbles to undergo stable cavitation, reveal that the resonance frequency diverges from the linear approximation as the pressure amplitude is increased. The shift in resonance, to lower frequency values, is found to be more pronounced for larger bubbles with the calculated value differing by up to 40% from the linear approximation. The results of this simulation might be potentially useful in preparation of formulations of ultrasound contrast agents with the specifically desired features, such as for instance resonance frequency.     

Enantioselective olefin epoxidation using novel biphenyl and binaphthyl azepines and azepinium salts

Homologous biphenyl and (diastereomeric) binaphthyl tertiary azepines and quaternary iminium salts were prepared from (S)- and (R)-3,3-dimethylbutan-2-amine. Both the amines and iminium ions behave as effective catalysts for the enantioselective epoxidation of unfunctionalized olefins (ee up to 87%).     

Analysis of 17β-Estadiol from Sewage in Coastal Marine by Surface Plasmon Resonance Technique

In this study, surface plasmon resonance （SPR） for monitoring 17β-eatradiol （E2） was developed. The small molecule E2 was immobilized on a CM5 sensor chip for an indirect competitive immunoassay to detect E2. The SPR response bahed on the antigen-antibody reaction was measured by injecting the sample solution into the flow system. The limitation of detection was 0.445 μg/L. The developed SPE-SPR system was applied to analyze the seawater samples. Recovery of E2 was 91.6%-93. 1%. Relative standard deviations（RSD） for the E2 assay were between 10.9%-15.1% （n = 3）. The range of determination of E2 samples from the sewage in the coastal marine environ-ment was between ND（lower than detection limit） and ca. 11.78 ng/L.     

Determination of organophosphate and carbamate pesticides based on enzyme inhibition using a pH-sensitive fluorescence probe

A flow injection system for the determination of organophosphate and carbamate pesticides is described. A sensitive fluorescence probe was synthesized and used as the pH indicator to detect the inhibition of the enzyme acetylcholinesterase (AChE). The percentage inhibition of enzyme activity is correlated to the pesticide concentration. Several parameters influencing the performance of the system are discussed. The detection limits of 3.5, 50, 12 and 25 μg/l for carbofuran, carbaryl, paraoxon and dichlorvos, in pure water, respectively were achieved with an incubation time of 10 min. A complete cycle of analysis, including incubation time, took 14 min. The detection system has been applied to the determination of carbofuran in spiked vegetable juices (Chinese cabbage and cole), achieving recovery values between 93.2 and 107% for Chinese cabbage juice and 108 and 118% for cole juice at the different concentration levels assayed.     

Constructing chiral diazoacetoacetates by enantioselective catalytic Mukaiyama aldol reactions

Asymmetric catalysis of Mukaiyama aldol addition reactions of methyl 3-TMSO-2-diazo-3-butenoate 4 with aromatic aldehydes using AgF/(R)-BINAP at −20 °C produces chiral diazoacetoacetates in high chemical yields and with high enantiocontrol.     

Isomeric anthracene diimide polymers

N-type semiconducting polymers are attractive for organic electronics, but desirable electron-deficient units for synthesizing such polymers are still lacking. As a cousin of rylene diimides such as naphthalene diimide (NDI) and perylene diimide (PDI), anthracene diimide (ADI) is a promising candidate; its polymers, however, have not been achieved yet because of synthetic challenges for its polymerizable monomers. Herein, we present ingenious synthesis of two dibromide ADI monomers with dibromination at differently symmetrical positions of the ADI core, which are further employed to construct ADI polymers. More interestingly, the two obtained ADI polymers possess the same main-chain and alkyl-chain structures but different backbone conformations owing to varied linking positions between repeating units. This feature enables their different optoelectronic properties and film-state packing behavior. The ADI polymers offer first examples of conjugated polymer conformational isomers and are highly promising as a new class of n-type semiconductors for various organic electronics applications.

Two anthracene diimide (ADI) polymers with the backbone conformational isomerism, new members of aromatic diimide polymers family, have been synthesized as a class of highly promising n-type semiconductors for organic electronics.     

Immunoassay of P-glycoprotein on single cell by capillary electrophoresis with laser induced fluorescence detection

The cellular mechanism based on P-glycoprotein (PGP) for its drug pump function has become very important in multidrug resistance (MDR) research. A method has been established to characterize PGP on single K562 cell by coupling capillary electrophoresis with laser induced fluorescence detection. A permeable intact cell after the immunoassay binding with fluorescence labeling antibody was injected into the capillary and directly separated without lysis. It was found that once 5-10 optional cells were detected in batch, the PGP amount on this cell line could be outlined and calculated clearly. The PGP amount on K562 MDR cell line is 3.88 times higher than that on K562 sensitive cell line. These two cell lines with immunoassay binding were also analyzed by injection of multi-cells in order to improve the throughput. A resistance factor so called multidrug resistance multiple (MRM) was introduced to evaluate the MDR difference between cell lines. The MRM values of the cell line K562 measured by single cell analysis are well correlated with those by flow cytometry, which also prove the validity of our method in single cell analysis for the possibility of cancer diagnosis, pharmacokinetics and drug screening in future.