Performance evaluation of polycyclic aromatic hydrocarbons analysis in sediment from proficiency testing with metrological reference values

This paper describes a metrological approach to evaluate the measurement capability of laboratories participating in two proficiency testing (PT) programmes involving the analysis of five polycyclic aromatic hydrocarbons (PAHs) in sediment samples. Reference values of PAHs in the programmes for performance assessment were obtained from an accurate isotope dilution gas chromatography mass spectrometry (ID-GCMS) method which was thoroughly validated and verified. Isotope dilution mass spectrometry (IDMS) technique usually has a well-defined measurement uncertainty budget and a traceability link to an International System of Units. Provision of the metrological reference values in PT enables the establishment of a technical platform to assess the actual competence of the participating laboratories in sediment PAHs analysis. Results of the PT programmes showed that about 80 % of the laboratories employed gas chromatography in their analyses and the remaining used liquid chromatography. Irrespective of the techniques being used, however, the majority of the participating laboratories were observed to underestimate values in which the mean values of the five reported PAHs were less than those of the ID-GCMS-derived reference values by 13–20 %. Only 41–44 % of the participating laboratories were able to achieve satisfactory z-scores. The present study revealed that the reinforcement of the capability for accurate measurement of PAHs in sediment samples in laboratories worldwide should be addressed.     

Effect of synthesis conditions on the mechanism of reversible inhibition in the TEMPO-mediated polymerization of 4-vinylpyridine

The effects of polymerization conditions (the types and concentrations of initiator and solvent, the TEMPO-to-initiator molar ratio, and temperature) on the kinetics and mechanism of pseudoliving radical polymerization of 4-vinylpyridine mediated by the nitroxide TEMPO are studied. The key quantitative parameters of the process are calculated: namely, the rate constant of reinitiation, the rate constant of inhibition, and the product of the propagation-rate constant and the pseudoliving equilibrium constant. The optimum conditions for the controlled synthesis of poly(4-vinylpyridine) mediated by TEMPO are ascertained.     

Synthesis and properties of near IR induced self-healable polyurethane/graphene nanocomposites

A series of self-healable polyurethane (SHPU)/modified graphene (MG) nanocomposites were synthesized from poly(tetramethylene glycol) (PTMG) and 4,4′-methylene diphenyl diisocyanate (MDI) with minute amounts (0–1 wt%) of MG which was chemically modified graphene oxide (GO) with phenyl isocyanate and reduced in the presence of phenylhydrazine.     

Mild and Efficient Deoxygenation of Sulfoxides with a WCl6/Indium System

Dialkyl, diaryl, and aryl alkyl sulfoxides can be rapidly converted to the corresponding sulfides with a WCl₆/In system in excellent yields under mild conditions.     

Topography and field effects in the inner side of microvia hole using ToF‐SIMS

We have developed a simple and powerful method, which is called ‘angled sample holder method’, to characterize a topographic structured sample such as microsized via hole of ball grid array using time‐of‐flight SIMS. The diameter of via holes was 100 µm and the depth was 70 µm. To remove the shaded area by incidence primary ion beam and to extract secondary ions from the bottom of a via hole, several types of angled sample holders with compensation steering plate were applied on the basis of simulation results using SIMION code. And the analyses using angled sample holder method enabled us to characterize the bottom and side wall of a via hole in clear. Copyright © 2014 John Wiley & Sons, Ltd.     

Brønsted Acid–Catalyzed Meyer–Schuster Rearrangement for the Synthesis of α,β-Unsaturated Carbonyl Compounds

An efficient and simple protocol for the Meyer–Schuster rearrangement of propargyl alcohols into α,β-unsaturated carbonyl compounds has been developed using catalytic amounts of p-toluenesulfonic acid in 1,2-dichloroethane.     

Inclusion of thymol into cucurbiturils: density functional theory approach with dispersion correction and natural bond orbital analysis

Journal of Inclusion Phenomena and Macrocyclic Chemistry - Stability of inclusion complexes of thymol (a natural flavour) with cucurbit[n]urils was interpreted by using density functional theory...     

Effects of a High-Molecular-Weight Polysaccharides Isolated from Korean Persimmon on the Antioxidant,Anti-Inflammatory,and Antiwrinkle Activity

Persimmon (Diospyros kaki), a familiar and widespread fruit worldwide, is known to exhibit several physiological effects because of the presence of pharmacologically active compounds called phytochemicals. However, its high-molecular-weight compounds, particularly polysaccharides, have not been extensively studied. In this study, D. kaki extract (DK) was fractionated into low- and high-molecular-weight fractions (DK-L and DK-H, respectively) through ethanol fractionation, and their effects on antioxidant, anti-inflammatory, and antiwrinkle activities were investigated by an in vitro system. DK-H contained significantly higher contents of neutral sugar, uronic acid, and polyphenols compared to DK and DK-L. Furthermore, DK-H exhibited significantly improved pharmacological activities, such as antioxidant, anti-inflammatory, and antiwrinkle properties, compared to those of DK and DK-L, demonstrating that DK-H may play an important role in mediating the beneficial effects of persimmon. Sugar composition analysis and molecular characterization indicated that DK-H consisted of a galacturonic acid (GalA)-rich polysaccharide with a molecular weight of >345 kDa that mainly comprised GalA and small amounts of neutral sugar and polyphenol residues. These results suggest that the bioactive fraction DK-H is likely to be a GalA-rich pectic polysaccharide containing a small number of polyphenol residues, which may be a novel candidate in the pharmaceutical and cosmeceutical industries.     

Effects of gamma irradiation on morphological changes and biological responses in plants

This review discusses the morphological changes and biological responses of plants irradiated with gamma rays. Seedlings exposed to relatively low doses of gamma rays (1-5 Gy) developed normally, while the growth of plants irradiated with a high dose gamma ray (50 Gy) was significantly inhibited. Based on TEM observations, chloroplasts were extremely sensitive to gamma irradiation compared to other cell organelles, particularly thylakoids being heavily swollen. In addition, some portions of the mitochondria and endoplasmic reticulum were structurally altered, for example, distortion and swelling. The cerium perhydroxide deposition, as a maker for H(2)O(2) deposition, was typically manifest on the plasma membranes and cell walls of the tissues from both the control and irradiated plants. However, the intensities of cerium perhydroxide deposits (CPDs) were remarkably increased in the plasma membranes and cell walls of pumpkin tissues such as petiole, cotyledon, hypocotyl and especially leaf after gamma irradiation. These observations are in good agreement with the results of H(2)O(2) content in all tissues. The immuno-localization analysis for peroxidase (POD) on the tissues from pumpkin plant showed the same pattern between the control and irradiated plants, but the density of gold particles as indication of POD localization was significantly increased on the cell corner middle lamellae of parenchyma cells, especially in the petiole after gamma irradiation. However, accumulation and localization of H(2)O(2) and POD in vessels were not significantly different between both plants. The accumulation and localization of both H(2)O(2) and POD were differentially affected by gamma irradiation depending on the different tissue types. The deposition of both H(2)O(2) and POD in parenchyma cells appeared much higher than in vessels, suggesting that the former is more sensitive than the latter against gamma rays.