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Mycotoxin contamination is a globally concerned problem for food and agricultural products since it may directly or indirectly induce severe threats to human health. Sensitive and selective screening is an efficient strategy to prevent or reduce human and animal exposure to mycotoxins. However, enormous challenges exist in the determination of mycotoxins, arising from complex sample matrices, trace-level analytes, and the co-occurrence of diverse mycotoxins. Appropriate sample preparation is essential to isolate, purify, and enrich mycotoxins from complicated matrices, thus decreasing sample matrix effects and lowering detection limits. With the cross-disciplinary development, new solid-phase extraction strategies have been exploited and integrated with nanotechnology to meet the challenges of mycotoxin analysis. This review summarizes the advance and progress of solid-phase extraction techniques as the methodological solutions for mycotoxin analysis. Emphases are paid on nanomaterials fabricated as trapping media of solid-phase extraction techniques, including carbonaceous nanoparticles, metal/metal oxide-based nanoparticles, and nanoporous materials. Advantages and limitations are discussed, along with the potential prospects.

Phthalate esters (PAEs) are ubiquitous pollutants in the environment with toxicological and epidemiological effects for humans. As one of the daily necessities, edible plant oil is an important exposure source of PAEs, due to the inevitable contact with PAE-containing materials and the intrinsic lipid solubility of PAEs. However, limited information is currently available on the exposure risk of PAEs in commercial plant oil. This study was aimed at investigating the occurrence and risk assessment of PAEs in plant oils with a high-frequency import rate in west China. The analysis method was referenced to the Chinese national standard for the determination of PAEs in food. Results indicated that PAEs (mainly including DBP and DEHP) were ubiquitous contaminants in imported plant oils with the detectable rate being up to 56.83% in 366 samples. The detected concentrations were in the range of 0.10-3.20 mg kg

Magnetic solid-phase extraction (MSPE) strategy based on the Fe

The complexation behaviour towards lanthanide (Ln) ions with quercetin (Q) was evaluated both in homogeneous phase and in liquid-liquid extraction process. As confirmed by UV–vis, fluorescence techniques and 1H NMR titration, Q can bind lanthanide ions through 4‑carbonyl and 3-hydroxyl of ring C with the stoichiometric ratio of 2:1 (Q:metal) in methanol solution. The binding constants for Q and Eu(III) (K1 = (3.87 ± 0.20) × 104 M−1, K2 = (2.56 ± 0.15) × 103 M−1) are slightly higher than that of Q-La(III) (K1 = (2.01 ± 0.15) × 104 M−1, K2 = (1.53 ± 0.12) × 103 M−1) and Q-Yb(III) (K1 = (1.73 ± 0.12) × 104 M−1, K2 = (1.25 ± 0.22) × 103 M−1). Solvent extraction revealed that the extractability of Ln(III) was relevant to the acidity and salinity of aqueous phase and extraction efficiency was Eu(III) > La(III) > Yb(III) at the same acidity.

Purpose.In order to find key risk factors of chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS) among urban men in China, an age-matched case-control study was performed from September 2012 to May 2013 in Yichang, Hubei Province, China.Methodology.A total of 279 patients and 558 controls were recruited in this study. Data were collected by a self-administered questionnaire, including demographics, diet and lifestyle, psychological status, and a physical exam. Conditional logistic regression model was used to analyze collected data.Results.Chemical factors exposure, night shift, severity of mood, and poor self-health cognition were entered into the regression model, and result displayed that these four factors had odds ratios of 1.929 (95% CI, 1.321–2.819), 1.456 (95% CI, 1.087–1.949), 1.619 (95% CI, 1.280–2.046), and 1.304 (95% CI, 1.094–1.555), respectively, which suggested that these four factors could significantly affect CP/CPPS.Conclusion.These results suggest that many factors affect CP/CPPS, including biological, social, and psychological factors.

Pure and F, GeO2-doped silica glass cut from fiber preforms prepared by plasma assisted chemical vapor deposition(PCVD) were investigated by ultraviolet absorption spectroscopy. The ultraviolet absorption characteristics of these glasses were also studied after UV laser irradiation and heating treatment. It was found that absorption band near 240 nm assigned to GODC was found both in GeO2-doped and F-GeO2 co-doped silica glass, but absorption intensity of the latter was lower than that of the former. It’s because F can react with GODC and GeE’ simultaneously and reduce their concentration. After irradiation, UV absorption change of F-GeO2 co-doped silica glass was weaker than that of GeO2-doped silica glass,it thus can be concluded that introduction of F could depress the UV absorption of GeO2-doped silica core effectively.

A multi-clad waveguide, which provide more bandwidth for WDM with S+C+L bands, is illustrated in this study. The bending loss is optimized for the FTTH applications. The fiber is manufactured by PCVD process; the test results are identical with the theoretic calculation. This fiber has nearly flat dispersion from 1460 nm to 1625 nm. The MFD at 1310 nm and 1550 nm are 8.2 and 9.4 µm, respectively. Bending loss is less than 0.1 dB/Turn at a bending radius of 7.5 mm. With low-water-peak manufacture technologies, the fiber is suitable for FTTH applications.

Pure and fluorine-doped silica glass were fabricated by plasma chemical vapour deposition (PCVD) and characterized using Raman and infrared spectrum. The change in Raman intensity of 945 cm−1 peak, relating to ≡Si—F stretching vibration, agrees with the change of F content. Compared with measured wavenumber in IR spectrum, the calculated absorption wavelength confirms the incorporation form of F into the glass, the detail of which is a tetrahedron with a Si atom in the center coupled with one F atom and three network O atoms. Such structure identification may be useful for explaining some properties of F-doping silica glass.

We report an investigation of design, fabrication and measurement for photonic crystal fibers developed by YOFC in three years. The development status of PCFs and their applications are synoptically investigated. In the part of fabrication process, a technology route of PCF fabrication are reviewed, and the process principle, process control and realization method are introduced mainly, related to process bottlenecks. Based on different PCFs designed respectively by Beam-Propagation Method, Plane-Wave Expansion Method or FDTD and the above fabrication process, we probed into and realized some kinds of PCF samples. The structure parameters, cross-section morphologies, attenuation and dispersion properties for PCF samples are respectively investigated. We also debate upon the potential application of PCF field.

With the rapid development and widely used of fiber grating, the demand of high quality photosensitive fiber has increase greatly. Based on the plasma chemical vapor deposition (PCVD) process, the Ge/F co-doped photosensitive fiber was developed. Through analyze the fiber's photosensitivity, study the fiber's photosensitivity influenced by the doping process. The data indicate that the high F doped (5%) Ge/F photosensitive fiber's grating has the 80% reflectivity, much lower than the low F doped(1%) Ge/F photosensitive fiber's 94%. The F doped content can influence the fiber's photosensitivity distinctly.

Single mode fiber (SMF) has been used widely in local and access network since the early 1980's. Fiber loss reduction will accelerate the construction of various transmission systems with longer repeater spacing. It has been reported that the transmission loss in SMF increases due to residual stress, which is caused by viscosity mismatch between the core and cladding material. The idea of viscosity matching is to match the viscosity of core and cladding doping to minimize the viscosity difference on the cross-section of the fiber or preform. The dopant concentrations can be chosen so that the viscosity of core and the cladding are equal in ideal step index fiber. However, all the reported viscosity-matching design is based on single dopant, for example, only GeO2 is doped in the central core and only F in the cladding. In this paper, optical loss reduction through viscosity-matched design for the SMF with GeO2-F codoped silica core and cladding is described. The impact of viscosity-matching on optical loss of silica-based single-mode fiber has been investigated in detail theoretically and experimentally based on PCVD fiber. For PCVD optical fiber, F is introduced in core is to reduce the water peak. Single mode optical fiber with low attenuation fabricated by PCVD process can be gotten through viscosity-matching design between core and cladding. Viscosity-matching can reduce the sensitivity of attenuation to drawing tension. The model for estimating the viscosity matching has been deduced, which can not only be used for conventional SMF but also for the fiber with arbitrary index profile.

In this paper, a novel fiber manufacturing process based on PCVD is introduced. The fiber drawing length per preform can reach more than 5,000 km and the cost is lower. The fiber shows better optical and geometrical properties. Such large size preform combines the advantages of PCVD process for high quality and OVD process for low cost. This PCVD RIC process will be helpful for increasing the ability of inside vapor deposition process.

Low water peak single mode fiber (LWP-SMF) fabricated by PCVD based process has been described. Based on the whole process of PCVD fiber, the hydroxyl contamination and its sources are as follows: (1) raw material, such as SiCl4, GeCl4, O2, C2F6, substrate tube and jacket tube; (2) leakage of the system including PCVD and collapsar; (3) surface contamination. The latter purification of deposited glass is extremely difficult, so the most effective solution is prevention. The hydroxyl contamination prevention and elimination measures, such as purity improvement of raw material, online purification during PCVD, surface absorption reduction and dilution effect with large preform, which are the key factors for LWP-SMF fabrication by PCVD based process, are revealed. Large scale production has revealed that LWP-SMF can be fabricated by PCVD based process combined with above mentioned process innovation. PCVD LWP-SMF complies with or exceeds the ITU recommendation G.652 (C and D) and IEC 6093-2-50 type B 1.3 optical fiber specification. With further development of high purity raw material, machine-airproof improvement and larger preform (above 150mm) combined with material composition and structure optimization in optical fiber or preform, high performance PCVD LWP-SMF with lower water peak or even zero-OH performance will be achieved. Besides, other type of optical fiber with low water peak, such as G.653, G.655 and G.656, can also be made with the advanced PCVD based process.

Quartz optical fiber or preform is composed of core and cladding with different refractive index (RI). Their compositions are different from the core to cladding in order to acquire desired RI profile. The physical properties from core to cladding are different, such as thermal expansion coefficients, thermal capacity and glass transition temperatures, which have much effect on the properties of optical fiber. The material composition and structure in PCVD single mode (SM) fiber was introduced in this paper. The composition of PCVD SM fiber was SiO 2 -GeO 2 -F-(Cl). F acted as a water-getter to reduce water peak besides lowering the RI of quartz glass and GeO 2 -F co-deposition was adopted in PCVD fiber. The functional graded material (FGM) design in PCVD SM fiber, which can reduce the attenuation, PMD, splicing loss and improve microbending resistance, was analyzed and discussed.

A kind of new single mode optical waveguide has been designed and it is prepared by PCVD process. The design and the characteristics of the optical waveguide are studied and discussed in the paper. The waveguide structure of multi-core layers is adopted. Two types of designs, concept-a and concept-b are analyzed and compared. The characteristics of the optical waveguide based on concept-b are very excellent. It is a kind of non-zero dispersion shift optical fiber (NZ-DSF). The zero dispersion wavelength(λ 0 ) is about 1390nm and the absolute value of dispersion from 1200nm to 1625nm is lower than 14 ps/(nm×km). The typical mode field diameter of this optical waveguide is 9.1 um. However, its cut-off wavelength(λ c ) is not higher than 1200nm and it is much lower than that of existing non-zero dispersion shift optical waveguide, but the bending resistance property of the optical waveguide is excellent. The Macro-bending loss at 1625nm is about 0.019 dB/turn when the spindle diameter is 32mm. Besides, it has low attenuation in the broad spectrum; especially the water peak is lower than 0.34 dB/km. It has super-broad spectrum, from 1200nm to 1625nm, transmission capability as single mode optical waveguide, so it can be used in the high transmission speed DWDM system.