Determination of Polycyclic Aromatic Hydrocarbons in Traditional Chinese Medicine Raw Material,Extracts, and Health Food Products

The four polycyclic aromatic hydrocarbon markers (PAH4) of benzo[a]anthracene (BaA), chrysene (Chr), benzo[b]fluoranthene (BbF), and benzo[a]pyrene (BaP) are indicators showing polycyclic aromatic hydrocarbon (PAH) contamination levels in Chinese medicine raw materials (CMRMs), extracts and health food products; Samples of herbal medicine, herbal extracts, and food supplements were extracted with n-hexane, then cleaned up sequentially on Florisil and EUPAH solid-phase extraction (SPE) columns. A gas chromatography–mass spectrometry method for the determination of four polycyclic aromatic hydrocarbon markers in Chinese medicine raw material, extracts, and health food products was established; In spiked-recovery experiments, the average recovery was about 78.6–107.6% with a precision of 2.3–10.5%. The limit of quantification (LOQ) and limit of detection (LOD) of the PAH4 markers in this method were 2.0 μg/kg and 0.7 μg/kg, respectively. When the developed method was utilized to determine PAH4 contents in 12 locally available health food products, 3 samples contained over 10.0 μg/kg BaP, and 5 samples contained over 50.0 μg/kg PAH4. The European Union (EU) limits for BaP and PAH4 are 10 and 50.0 μg/kg, respectively; therefore, more attention must be drawn to the exposure risk of BaP and PAH4 in CMRMs, their extracts, and health food products. According to the risk assessment based on the Margin of Exposure (MOE) method, it is recognized that the products mentioned in this study pose a low risk.     

光敏热成像材料的化学增感进展

本文综述了近年来光敏热成像(PTG)材料在化学增感方面取得的相关新进展.在分析文献结果以及结合作者相关实验数据的基础上提出了进行化学增感的有效方法,即提高卤化银外部潜影的形成效率,或者提高银离子供应源在显影过程中的热迁移能力.文章对PTG材料在化学增感方面的发展提出了一些见解和想法.     

0.5PZN-0.5PZT压电陶瓷拉曼散射研究

PZT基多元系压电陶瓷在三方相含量与四方相含量相等的准同型相界处(MPB)具有极为优异的压电性能。文章采用拉曼散射方法研究了0.5PZN-0.5PZT陶瓷体系中三方-四方相共存与弥散相变现象。研究发现,与纯PZT相比,0.5PZN-0.5PZT体系拉曼谱呈明显宽化特征,表明体系弛豫性较强,依据介温谱计算出弥散因子γ高达1.71。通过对拉曼谱峰进行Gauss函数拟合,定量计算三方相R₁模式与四方相E(3TO)和A₁(3TO)模式相对强度,以及四方相E(4LO)和A₁(3LO)模式与三方相R_h模式相对强度,结果表明0.5PZN-0.5PZT体系三方相与四方相含量相等,组成位于准同型相界,该结果得到XRD相分析验证。电学测量表明0.5PZN-0.5PZT陶瓷压电性能优异：k_p=0.66, d₃₃=425 pC/N,适宜作为压电致动器材料使用。     

Radiophotolumenescence of Irradiated Polymethylmethacrylate Doped with Some Charge Transfer Complexes

Radiophotolumenescence (RPL) of irradiated and non irradiated thin films of polymethylmethacrylate (PMMA) doped with anthracene (Anth) as a donor, and tetracyanoquinodimethane (TCNQ) as an acceptor, has been investigated. The RPL – glow spectrum was recorded to study the characterizing emission bands from the point of view of glow peak position and intensity and hence the prospective relative sensitivities. RFL – signal fading after one month storage in dark at room temperature post gamma irradiation was also studied. PMMA doped with 6:4 donor to acceptor ratio has been proved to be the most sensitive one with less fading regarding gamma detection. On the other hand 2 Anth: 8 TCNQ was found to be the proper dopant concentration ratio for thermal neutron detection.     

Application of Autoradiography to the Investigation of New Doping Techniques of Semiconductor Materials

The development of technology of new semiconductor devices requires fundamental studies of a number of phenomena taking place in semiconductors during the doping process or accompanying the doping process.

These studies are concerned with the following problems:

1. Diffusion of gold in silicon and the effect of diffusion layers (particularly phosphorus layers) and epitaxial silicon layers on the distribution of gold in thin silicon plates.

2. Distribution of admixtures in silicon introduced with the aid of the ion implantation technique. Our studies concerned with the second of the above mentioned problems comprised an autoradiographic examination of the homogeneity of the beam of phosphorus ions implanted in silicon, and a study of some apparatus factors and of the purity of the basic material on the implantation.     

Development of Piezoelectric Immunosensor for the Detection of Probiotic Bacteria

A Quartz Crystal Microbalance (QCM) based direct immunosensor was developed for real-time detection of probiotic bacteria. To optimize the immunosensor system, model measurements were carried out with bovine serum albumin (BSA) and anti-BSA IgG (a-BSA) antibody. During the model experiments, two kinds of self-assembled monolayers were created to compare their efficiency on antigen binding. Sulfosuccinimidyl 6-[3-(2-pyridyldithio)propionamido] hexanoate (sulfo-LC-SPDP) and 16-mercapto-hexadecanoic acid (MHDA) cross-linking agents were used for immobilizing anti-BSA antibody onto the gold surface of the AT-cut quartz wafer. Two different measuring procedures, flow-through and stopped-flow methods, were applied, and the frequency responses obtained by both analytical methods were compared.

After the model experiments probiotic bacteria, Bifidobacterium bifidum O1356 and Lactobacillus acidophilus O1132 serotypes were detected from buffer solution and from real samples (spiked milk samples, acidophilus, and bifidus milk samples).

Using the novel immunosensor, the target bacteria could be detected in the range of 10⁴–10⁷ colony-forming units (CFU)/ml within 60 minutes. The selectivity of a-Bifidobacterium bifidum and a-Lactobacillus acidophilus antibody coated sensors were also tested.     

Synthesis of aqueous dispersion of graphenes via reduction of graphite oxide in the solution of conductive polymer

Graphene sheets were produced by chemical reduction of graphite oxides in the solution of ionic conductive polymer, Nafion. The obtained graphene, coated with Nafion, can be re-dispersed in water, and readily forms stable dispersed state. The polymer-coated graphene had been characterized by FT-IR spectroscopy, UV-vis and X-ray photoelectron spectroscopy (XPS). The PEDOT film with Nafion-coated graphene increased significantly from 0.25 S/cm for pure PEDOT film and reached 12 S/cm. Further, the films of PEDOT doped Nafion-coated graphene had also higher conductivities compared to films doped PSS-coated graphene.     

Plasma Treatment Enhanced Magnetic Properties in Manganese Doped Titanium Nitride Thin Films

The ferromagnetic manganese doped TiN films were grown by plasma assisted molecular beam epitaxy on MgO(001) substrates. The nitrogen concentration and the ratio of manganese at Ti lattice sites increase after the plasma annealing post treatment. TiN(002) peak shifts toward low angle direction and TiN(111) peak disappears after the post treatment. The lattice expansion and peak shift are mainly ascribed to the reduction of nitrogen vacancies in films. The magnetism was suppressed in as-prepared sample due to the pinning effect of the nitrogen vacancies at defect sites or interface. The magnetism can be activated by the plasma implantation along with nitrogen vacancies reduce. The decrease of nitrogen vacancies leads to the enhancement of ferromagnetism.     

The sp2 and sp3 fractions of unknown carbon materials: electron energy-loss near-edge structure analysis of C-K spectra acquired under the magic-angle condition by the electron nanobeam technique

A method is described for the quantification of the sp², sp³ and intermediate hybridizations in several carbon (C) material samples. Electron energy-loss near-edge spectra were acquired using fast electrons (120 keV) in an electron microscope in nanobeam configuration under the so-called ”magic-angle” condition, and were analysed to extract the sp² and sp³ fractions, and identify the possible mixed sp^2+ε hybridizations. The method consists in projecting the unknown spectra on a basis made up of pure sp² and sp³ spectra, obtained under the same experimental conditions from graphite and diamond crystals, respectively. The residual spectra contain information about the intermediate hybridizations sp^2+ε occurring in the samples. The method was successfully tested on “ab initio” numerically generated spectra relative to amorphous C materials. Finally, it was applied to actual C amorphous and pyrolytic samples, and results were compared to those obtained by the most commonly used, conventional ”three-Gaussian” method. The combined application of electron diffraction and spectroscopy, in the nanobeam configuration, yielded useful information about the atomic and electronic structure from very small volumes of the unknown C material.     

An unexpected generation of magnetically separable Se/Fe3O4 for catalytic degradation of polyene contaminants with molecular oxygen

Selenization of Fe₂O₃ with NaHSe led to Se/Fe₃O₄. The unexpected generation of Fe₃O₄ attributed to the reduction conditions of the reaction, and the resulted magnetic features of the material facilitated its separation in practical applications. Owning to the synergistic effect of Se with Fe, the material was especially active to catalyze the oxidative C=C scission using O₂ as mild oxidant. The technique has been successfully applied in polyene degradation project, which is of profound practical values for the treatment of the polyene pigment pollution and may be applied in the food and pharmaceutical industry.