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Investigations on the molecular composition of coal pyrolysis products can help us to improve nonfuel utilization of coal. Meanwhile, the molecular composition of coal pyrolysis products is also influenced by the characteristics and depositional environment of coal. However, due to the extremely complex nature of coal, direct investigation of the molecular composition of coal pyrolysis products is still a challenge. In the present work, the data of the molecular composition of bituminous coal pyrolysis products are obtained by online pyrolysis coupled to comprehensive two-dimensional gas chromatography and mass spectrometry (online py-GC×GC-MS) and are divided into nine molecular groups depending on the aromaticity of the pyrolysis products and separating power of the GC×GC-MS. Chemometric tools, hierarchical cluster analysis, and principal component analysis are employed to reveal the correlations among the molecular composition of coal pyrolysis products and coal characteristics. The results show that the nine molecular groups of bituminous coal pyrolysis products can be divided into two clusters, the "aromatic group" and the "aliphatic group", and that the eight coals are divided into three clusters, all of which can be interpreted by the depositional environments and δ13CVPDB values of coals. Moreover, a simple and empirical equation for estimation of coal tar from hydropyrolysis can be obtained depending on the chemometric results of the molecular composition of the coal pyrolysis products. By application of chemometrics, the molecular composition of coal pyrolysis products can provide preference to industrial utilization of coal.

Background Despite advances in the treatment of acute promyelocytic leukemia (APL) with all-trans-retinoic acid (ATRA), its underlying mechanism has not been fully elucidated. The oncogenic microRNA cluster miR-17-92 modulates multiple cellular processes, including survival, proliferation, and apoptosis. However, the role of miR-17-92 and its regulation has not yet been documented for APL. Methods We analyzed miR-17-92 expression in APL samples and cell lines by qRT-PCR. The expression of c-Myc was measured by western blot. Cell differentiation was assessed by measuring the surface CD11b antigen expression by flow cytometry analysis. Results We observed that miR-17-92 was upregulated in APL compared with healthy donors. Furthermore, we demonstrated that expressions of c-Myc and miR-17-92 are markedly suppressed during ATRA-induced NB4 cell differentiation. Importantly, we also demonstrated that miR-17-92 is directly regulated by c-Myc during the granulocytic differentiation of APL cells. Finally, the overexpression of miR-17-5p blocks ATRA-induced differentiation. Conclusions We report abnormal expression of the miR-17-92 cluster in APL cells, which is responsible for the differentiation block in blast cells in APL. In addition, we identified miR-17-92 as a target gene of c-Myc during ATRA-induced granulocytic differentiation.

An orthogonal test with four factors, namely temperature, time, type of rare-earth oxides (REOs) and REO content, was performed to obtain the optimised boriding parameters of TB2 alloy by pack bori...

We report an experimental investigation of Yb filler ion dynamics in partially filled skutterudite samples Yb xCo 4Sb 12 ( x=0.26 and x=0.4). From extended x-ray absorption fine structure (EXAFS) measurements at the Yb L2-edge, the mean-square displacements of the Yb fillers were extracted over a wide temperature range from 10 to 500 K. We found that the low-temperature dynamics of Yb fillers are described well using a harmonic oscillator approximation with Einstein temperatures of 70±5 K for both samples. This finding is consistent with the observed low-energy phonon mode at 5.3(5) meV in the inelastic x-ray scattering (IXS) data. However, the temperature dependence deviates from the harmonic approximation at high temperatures due to significant cubic anharmonicity, which was revealed in the EXAFS cumulant analysis. Our study also demonstrates that complementary information on filler dynamics in skutterudites can be acquired using EXAFS and IXS.

To investigate the relationship between the serum level of miR-9 and the progression of diabetic nephropathy (DN) and related molecular mechanisms. Thirty-five healthy subjects and 140 DN patients were divided into five groups: control, DN I–II, DN III, DN IV and DN V. Serum level of miR-9 was measured by real-time qPCR. Serum levels of vascular endothelial growth factor (VEGF), pigment epithelium-derived factor (PEDF) lipids, fasting glucose, insulin, hemoglobin A1c (HBA1c), creatinine, fibrinogen and insulin resistance (HOMA-IR) were also measured. The results show that the levels of miR-9, PEDF and VEGF are increased with DN progression (P

Endoplasmic reticulum (ER) stress plays an important role in metabolic diseases like obesity and type 2 diabetes mellitus (T2DM), although the underlying mechanisms and regulatory pathways remain to be elucidated. Here, we induced chronic low-grade ER stress in lean mice to levels similar to those in high-fat diet (HFD)–fed obese mice and found that it promoted hyperglycemia due to enhanced hepatic gluconeogenesis. Mechanistically, sustained ER stress up-regulated the deubiquitinating enzyme ubiquitin-specific peptidase 14 (USP14), which increased the stability and levels of 3′,5′-cyclic monophosphate–responsive element binding (CREB) protein (CBP) to enhance glucagon action and hepatic gluconeogenesis. Exogenous overexpression of USP14 in the liver significantly increased hepatic glucose output. Consistent with this, liver-specific knockdown of USP14 abrogated the effects of ER stress on glucose metabolism, and also improved hyperglycemia and glucose intolerance in obese mice. In conclusion, our findings show a mechanism underlying ER stress-induced disruption of glucose homeostasis, and present USP14 as a potential therapeutic target against T2DM.

Chronic myeloid leukemia (CML) is associated with chromosomal translocation t(9; 22), which results in formation of the BCR-ABL oncogene. CML is treated with tyrosine kinase inhibitors (TKIs), which target BCR-ABL, to eradicate BCR-ABL + cells. However, the TKI imatinib (IM) fails to eliminate quiescent leukemia stem cells (LSCs) in CML. In this study, we demonstrate that transcription factor TAL1 is down-regulated in CML LSCs by BCR-ABL, and IM triggers TAL1 mRNA expression. In addition, loss of TAL1 abrogates IM-induced CML cell apoptosis. RNA-seq analysis suggests that TAL1 expression may affect PI3K/AKT pathway. Moreover, depletion of TAL1 inhibits the expression of PTEN, which is a negative regulator of the PI3K/AKT pathway. Our results reveal an unexpected involvement of TAL1 in CML etiology and demonstrate that TAL1 may regulate PTEN expression and lead to inhibition of the PI3K/AKT pathway in the response of CML cells to TKI. These results implicate regulation of PTEN expression as a novel mechanism for the transcriptional regulatory networks of TAL1 in CML.

We present a method for large displacement measurement based on light rays interference. Instead of fiber's end-face, we launched the light from the side of fiber using a LED-Belt (LB) as a light source. The relative movement between the LB and optical fiber corresponds to displacement change, and associated intensity variation is detected through a power meter. The linear-displacement has been achieved up to 1 m with a sensitivity of about 1.532 nW/mm, which results in a resolution of 0.653 mm. The range can be further enlarged by increasing the length of fiber and LED-Belt depending on the application requirements. The proposed sensor method is simple, cost-effective, and easy to manufacture. The design structure also has significant potential for strain, pressure, and liquid level sensing as well as shape sensing.

We investigated the relationship between serum cystatin C levels and the prognosis of diabetic foot ulcerations (DFU). A population-based cohort study involving 1018 patients with type 2 diabetes was conducted. These patients recruited and divided into two groups: nondiabetic foot ulcer group (NDF, n = 865, 85.5%) and diabetic foot ulcer group (DFU, n = 147, 14.5%).After a 1-year-follow-up, DFUs were grouped into healing (n = 110, 74.8%) and nonhealing (n = 37, 25.2%) group based on the clinical prognosis. Compared with the healing group, the nonhealing group were older, had long diabetic duration and had significantly increased serum cystatin C concentrations in DFU (p 1.35 mg/L predicts more than sixfold increased risk of incurable foot ulceration.

C60-based magnetic nanospheres were synthesized by coating Fe3O4 nanospheres with silica, then modifying with 3-aminopropyltriethoxysilane as a linker and a C60 fullerene stationary phase. The morphologies, magnetic properties, infrared absorption and carbon content of magnetic nanospheres were studied by TEM, VSM, FTIR and carbon and sulfur analyzer. The magnetic nanospheres were employed for the magnetic solid-phase extraction (MSPE) of 16 polycyclic aromatic hydrocarbons (PAHs) in nine Chinese herbal medicines. The analyses were conducted by isotope dilution gas chromatography–mass spectrometry. The main parameters influencing the extraction, including extraction solvent, adsorbent amount, and extraction time were optimized. Method validation showed that the limit of detection (LOD) was 0.02–0.11 µg/kg, and the limit of quantification (LOQ) was 0.07–0.36 µg/kg. The spiked recoveries rates for 16 PAHs in white peony root were 84.7–107.2%. The relative standard deviation (RSD) was 1.7–8.4%. The established method was further used for the determination 16 PAHs in nine Chinese herbal medicines. Total content of 16 PAHs varied from 73.6 µg/kg (fructus lycii) to 2172.6 µg/kg (astragalus root). The results indicate that the pollution of PAHs in Chinese herbal medicines is serious. The established method can effective detect PAHs contamination in Chinese herbal medicines.

An automatic focus algorithm based on eight-neighborhood operator and least square planar fitting method is proposed to acquire the three-dimensional microscope focusing images in this paper. Firstly, eight-neighborhood operator and evaluation function are presented to locate the cells in the low-power microscope images in this paper. Then the automatic focus algorithm based on eight-neighborhood operator and least square planar fitting method is given to acquire the three-dimensional microscope cell images. After that, some experiments are given in the paper. The eight-neighborhood operator is compared with the traditional evaluation function in terms of the complexity of the operation and the effect of the evaluation function. Also, comparative experiments are conducted to verify the feasibility of the automatic focus algorithm in this paper. The experimental results showed that the proposed microscope automatic focus algorithm is effective and has a good fitting degree.

Filled skutterudites are workhorse materials in thermoelectric research. In recent years, double- or even triple-filling has emerged as a promising strategy to improve the thermoelectric figure of merit in skutterudites. For example, one type of filler is used to reduce thermal conductivity while the other filler is used to control the electron filling. However, in these studies, each filler atom is considered independent of each other and the interaction between the two filler atoms is completely ignored. Here we present our detailed investigation of the local structure of filler atoms in (${\mathrm{Yb},\mathrm{In})}_{x}{\mathrm{Co}}_{4}{\mathrm{Sb}}_{12}$ and show that significant interaction does exist between filler species. While Yb or In filler atoms at low concentration occupy the usual $2a$ filler site on their own, when Yb filler concentration goes above a critical value $x\ensuremath{\approx}0.15$, Yb pushes In atoms from the $2a$ site and into the $24g$ substitutional site replacing Sb atoms. This behavior is in stark contrast to that of Ga, which forms a dual-site defect even in the absence of Yb fillers. The temperature-dependent, extended x-ray absorption fine structure (EXAFS) data further reveal distinct lattice dynamical properties around In, Ga, and Yb filler atoms. Our findings point out that the filler interaction should be an important design consideration for new thermoelectric skutterudites.

We report comprehensive x-ray absorption spectroscopy studies at both the Ga $K$ edge and Yb ${L}_{2}$ edge to elucidate the local structure of Ga and Yb dopants in ${\mathrm{Yb}}_{x}{\mathrm{Ga}}_{y}{\mathrm{Co}}_{4}{\mathrm{Sb}}_{12}$. Our extended x-ray absorption fine structure (EXAFS) data confirm that Ga atoms occupy two crystallographic sites: one is the $24g$ site replacing Sb, and the other is the $2a$ site in the off-center void position. We find that the occupancy ratio of these two sites varies significantly as a function of the filling fraction of additional Yb, which exclusively occupies the $2a$ on-center site. At low concentrations of Yb, ${\mathrm{Ga}}_{24g}$ and ${\mathrm{Ga}}_{2a}$ dopants coexist and they form a charge-compensated compound defect proposed by Qiu et al. [Adv. Funct. Mater. 23, 3194 (2013)]. The ${\mathrm{Ga}}_{24g}$ occupancy increases gradually with increasing Yb concentration, and almost all Ga occupies the $24g$ site for the highest Yb concentration studied ($x=0.4$). In addition to the local structural evidence provided by our EXAFS data, we also present x-ray absorption near-edge structure (XANES) spectra, which show a small Ga $K$-edge energy shift as a function of Yb concentration consistent with the change from predominantly ${\mathrm{Ga}}_{2a}$ to ${\mathrm{Ga}}_{24g}$ states. Our result suggests that the increased solubility of Yb in Yb-Ga co-doped ${\mathrm{Co}}_{4}{\mathrm{Sb}}_{12}$ skutterudites is due to the increased ${\mathrm{Ga}}_{24g}$ electron acceptor, and thus provides an important strategy to optimize the carrier concentration in partially filled skutterudites.

ObjectiveSerum cystatin C (CysC) is a sensitive marker of kidney function and recent studies have shown that CysC plays a critical role in degenerative diseases in both the central and the peripheral nervous systems. The aim of this study was to explore the relationship between serum CysC and diabetic peripheral neuropathy (DPN) in patients with type 2 diabetes.MethodsIn total, 937 type 2 diabetic patients were enrolled in this cross-sectional study. Serum CysC concentration was measured by immunoturbidimetry. DPN was evaluated by neurological symptoms, neurological signs, neurothesiometer, and electromyogram.ResultsSerum CysC levels were significantly higher in DPN patients (1.3 (1.1–1.5) mg/l) compared with patients with signs of DPN (1.1 (0.9–1.3) mg/l, PPPPPConclusionsHigh serum CysC level is closely associated with DPN and may be a potential biomarker for DPN in type 2 diabetic patients.

In this work, we study the resonant transmission of acoustic waves through a plate with quasiperiodic surface corrugations. The transmission spectrum shows peculiar transmission peaks, which cannot be simply attributed to the coherent diffraction as recognized previously in structured hard plates (without sustaining internal modes), whereas come from the resonant excitation of the coupled Stoneley surface modes in the elastic plate. The excitation frequencies can be determined by the geometrical structure factor of the quasiperiodic lattice, combining with the dispersion relation of the surface modes.

An ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UHPLC-Q-TOF-MS) method was developed for determination of 39 veterinary drugs in Procambarusclarkii. Samples were extracted with acidified acetonitrile and purified with enhanced matrix removal-lipid (EMR-Lipid) adsorbent and graphitized multi-walled carbon nanotubes (GMWNTs). Extracts were analyzed by UHPLC-Q-TOF-MS. Target compounds were screened according to accurate mass, isotopic ratio, and retention time, and confirmed by library search. Target analytes were quantified using the chromatographic peak area of each compound. For each of the drugs of interest, calibration curves were linear in their respective ranges with correlation coefficients greater than 0.99. The limits of quantification (LOQs) were 3-15 μg/kg. The recoveries for target compounds spiked in Procambarusclarkii ranged from 62.4% to 105.8%, with relative standard deviations (RSDs) ranging from 2.5% to 13.5%. This method is simple, rapid, accurate, and suitable for simultaneous determination of 39 veterinary drugs, including sulfonamides, quinolones, and triphenylmethane, extracted from Procambarusclarkii.

We investigated the relationship between serum cystatin C levels and the prognosis of diabetic foot ulcerations (DFU). A population-based cohort study involving 1018 patients with type 2 diabetes was conducted. These patients recruited and divided into two groups: nondiabetic foot ulcer group (NDF, n = 865, 85.5%) and diabetic foot ulcer group (DFU, n = 147, 14.5%).After a 1-year-follow-up, DFUs were grouped into healing (n = 110, 74.8%) and nonhealing (n = 37, 25.2%) group based on the clinical prognosis. Compared with the healing group, the nonhealing group were older, had long diabetic duration and had significantly increased serum cystatin C concentrations in DFU (p 0.01). After adjustments for age, diabetes duration, renal function and infection control, multiple logistical regression analysis revealed that cystatin C remained associated increased risk of undesirable DFU outcome (OR = 7.279, 95% CI: 1.299-40.784, p 0.05). When divided into quartiles according to cystatin C levels, the healing rate of Quartile 4 was significantly lower (57.9%) compared with other groups (p 0.01). The odd is ratio (OR) analysis showed that the risk of undesirable DFU outcome in Quartile 4 was significantly higher (OR = 4.554, 95% CI: 3.14-5.12, p 0.05) compared with that in Quartile 1. We concluded that there was a strong and independent association between serum cystatin C and diabetic foot ulceration prognosis, cystatin C 1.35 mg/L predicts more than sixfold increased risk of incurable foot ulceration.

Vitamin D deficiency was reported to be associated with diabetic peripheral neuropathy. But the association in Chinese population and the screening value of vitamin D deficiency for diabetic peripheral neuropathy were unknown.A total of 861 patients with type 2 diabetes were recruited in this cross-sectional study. Vitamin D deficiency was defined as serum circulating 25-hydroxyvitamin D(25(OH)D) level 20 ng/mL. Peripheral neuropathy was evaluated by neurological symptoms, neurological signs, neurothesiometer and electromyogram.The patients with diabetic peripheral neuropathy had significantly lower serum 25(OH)D concentration (15.59 ± 7.68 ng/mL) and higher prevalence of vitamin D deficiency (80%) than patients with signs of diabetic peripheral neuropathy (17.66 ± 7.50 ng/mL; 64.5%) and non-DPN patients (18.35 ± 6.60; 61.7%) (all p 0.01). Spearman's correlation analysis showed that serum circulating 25(OH)D level was closely associated with DPN (r = 0.121) and signs of DPN (r = 0.111) (both p 0.01). After adjusting for all potential confounders, VDD was still linked with increased risk of DPN [odds ratio 2.59 (1.48-4.53)] (p 0.01). Logistical regression analysis further revealed that VDD was an independent risk factor for DPN (β = 0.88) (p 0.01). Receiver operating characteristic analysis indicated that serum 25(OH)D 17.22 ng/mL hinted the signs of DPN and serum 25(OH)D 16.01 ng/mL predicted the occurrence of DPN (both p 0.01).Vitamin D deficiency is an independent risk factor for diabetic peripheral neuropathy and may be a potential biomarker for peripheral neuropathy in Chinese patients with type 2 diabetes. Copyright © 2016 John WileySons, Ltd.

Ficolin-3, a soluble molecule of the innate immune system, has a primary role in the activation of the lectin pathway in the complement system. Considering that inflammatory mechanisms are involved in complement activation and take part in the pathophysiology of diabetic peripheral neuropathy (DPN), we conducted this study to explore the link between serum ficolin-3 and DPN in diabetic patients. A total of 466 diabetic patients were enrolled in this cross-sectional study. DPN was evaluated by neurological symptoms, neurological signs, neurothesiometer and electromyogram. The concentration of serum ficolin-3 was determined by enzyme-linked immunosorbent assay. The concentration of serum ficolin-3 was lower in DPN patients compared with non-DPN patients (18.73 ± 4.75 vs. 26.69 ± 5.68 ng/mL, P

Background Fibroblast growth factor 21 (FGF21) is an emerging metabolic regulator associated with glucose and lipid metabolism, and it is still unclear whether FGF21 is related to atherosclerosis. Here, we explored the potential link between FGF21 and lower extremity atherosclerotic disease (LEAD) in type 2 diabetic patients. Methods A cross-sectional study was conducted on 504 type 2 diabetic patients (283 men, 221 women). LEAD was defined by Ankle-brachial index (ABI) 0.05). Conclusions Serum FGF21 level independently and positively links LEAD in Chinese women with type 2 diabetes. The gender difference may be due to different estrogen levels.

An analytical method for the simultaneous determination of clopidol, sulfadiazine, sulfamethazine, sulfametoxydiazine, sulfamethoxypyridazine, norfloxacin, ofloxacin, ciprofloxacin, enrofloxacin in chickens by ultra performance liquid chromatography coupled with tandem quadrupole mass spectrometry (UPLC-MS/MS) in positive ion mode with multiple reaction monitoring (MRM) has been developed and validated. The samples were homogenized and extracted with acetonitrile. After defatted with high speed frozen centrifugation, the supernatant solution was evaporated and the residue was dissolved with the mobile phase and defatted with n-hexane. It was then analyzed with UPLC-MS/MS. The limit of detection of this method was 0.1 microg/kg, and the limit of quantification was 0.5 microg/kg. The average recoveries (spiked at the levels of 0.5, 1.0, 2.0 microg/kg) ranged from 81.5% to 97.6%, with the relative standard deviations between 2.1% and 8.9%. The results demonstrated that the method is simple, accurate and suitable for the identification and quantification of these drug residues in chickens.

We investigated the relationship between vibration perception threshold and diabetic retinopathy and verified the screening value of vibration perception threshold for severe diabetic retinopathy.A total of 955 patients with type 2 diabetes were recruited and divided into three groups according to their fundus oculi photography results: no diabetic retinopathy (n = 654, 68.48%), non-sight-threatening diabetic retinopathy (n = 189, 19.79%) and sight-threatening diabetic retinopathy (n = 112, 11.73%). Their clinical and biochemical characteristics, vibration perception threshold and the diabetic retinopathy grades were detected and compared.There were significant differences in diabetes duration and blood glucose levels among three groups (all p0.05). The values of vibration perception threshold increased with the rising severity of retinopathy, and the vibration perception threshold level of sight-threatening diabetic retinopathy group was significantly higher than both non-sight-threatening diabetic retinopathy and no diabetic retinopathy groups (both p0.01). The prevalence of sight-threatening diabetic retinopathy in vibration perception threshold25 V group was significantly higher than those in 16-24 V group (p0.01). The severity of diabetic retinopathy was positively associated with diabetes duration, blood glucose indexes and vibration perception threshold (all p0.01). Multiple stepwise regression analysis proved that glycosylated haemoglobin (β = 0.385, p = 0.000), diabetes duration (β = 0.275, p = 0.000) and vibration perception threshold (β = 0.180, p = 0.015) were independent risk factors for diabetic retinopathy. Receiver operating characteristic analysis further revealed that vibration perception threshold higher than 18 V was the optimal cut point for reflecting high risk of sight-threatening diabetic retinopathy (odds ratio = 4.20, 95% confidence interval = 2.67-6.59).There was a close association between vibration perception threshold and the severity of diabetic retinopathy. vibration perception threshold was a potential screening method for diabetic retinopathy, and its optimal cut-off for prompting high risk of sight-threatening retinopathy was 18 V.

BACKGROUND Vitamin D deficiency was reported to be associated with diabetic peripheral neuropathy. But the association in Chinese population and the screening value of vitamin D deficiency for diabetic peripheral neuropathy were unknown. METHODS A total of 861 patients with type 2 diabetes were recruited in this cross-sectional study. Vitamin D deficiency was defined as serum circulating 25-hydroxyvitamin D(25(OH)D) level

This communication presents a study on the simultaneous determination of thermolabile N-methylcarbamate and organophosphorus insecticides in cereal products by gas chromatography–mass spectrometry. The thermal stability of the multiple insecticides was evaluated with conventional hot splitless injection and on-column injection. The results obtained by GC–MS with these two injection techniques were compared in terms of the recovery, the limit of detection, the limit of qualification, and the reproducibility. With on-column injection, the pesticide recoveries in cereal samples were better than 82%, with relative standard deviations lower than 5.4%. The limits of qualification for most insecticides were in the range of 0.009–0.08 mg/kg, i. e. lower than the maximum residue limits established for insecticides in cereal products by the European Union. The long-term stability using on-column injection for analysis of insecticides in real samples was evaluated and normal chromatographic performance could be obtained within 50 analyses. The results revealed that it was possible for application of on-column injection in the analysis of thermolabile multiple insecticides in food sample after comprehensive sample clean-up, despite the highly contaminated nature of the column system.

An analytical method was established for the simultaneous determination of 204 pesticide residues in tea by ultra performance liquid chromatography coupled with quadrupole-time of flight mass spectrometry (UPLC-Q-TOF/MS). The samples were extracted with acetonitrile, and cleaned-up by solid phase extraction (SPE) with a Carb-PSA cartridge, eluted with acetonitrile-toluene (3:1, v/v), determined by UPLC-Q-TOF/MS and quantified by external standard method. A data base of the accurate mass numbers and a library which contains the 204 pesticides were established. The automatic retrieval of detection results was carried on according to the characteristics of the compound, such as accurate mass, retention time, isotopic ratio, and so on. Based on the above results, the qualitative identifications of the 204 pesticides were accomplished without the contrast of standard substances. The results indicated that this method can be used to determine the 204 pesticides in tea. At the three spiked levels of 10, 20, 50 µg/kg, mean recoveries for the 204 pesticides in tea were between 68. 1% and 117. 2%, with the relative standard deviations (RSDs) ranging from 3.1% to 18.9%. The limits of quantification for the 204 pesticides were lower than 10 µg/kg. The method has been applied to four positive samples, and the results generally accord with the detection results by the method of GB/T 23205-2008. This method has the characteristics of high efficiency, as well as high sensitivity and accuracy, which can meet the requirement of the determination of the 204 pesticides in tea.

For the analysis of organosulfur compounds in fresh garlic, a gas chromatographic/mass spectrometric (GC/MS) method is proposed using temperature-programmable cold on-column injection and cold solvent extraction of the fresh garlic. This was carried out under the conditions of cryogenic process from extraction to column separation. Hence, a valid identification can be achieved about the primary components in garlic extract before thermo-degradation. The obtained results showed that 3-vinyl-4H-1, 2-dithiin and 2-vinyl-4H-1, 3-dithiin were the major compounds in the garlic extract with minor amounts of S-methyl methanethiosulfinate, diallyl disulfide, trisulfide-di-2-propenyl. A comparative study of chemical compounds was performed between garlic extract by cold solvent and garlic oil by stream distillation. The degradation and formation of major organosulfur compounds in the garlic extract were also explored.

A new method based on matrix solid-phase dispersion (MSPD) extraction with neutral alumina and co-column purification with graphitized carbon black has been developed to determine aflatoxins B1, B2, G1, G2 in hot chilli products. The method includes liquid chromatography and fluorescence detection with on-line post-column derivatization with bromine. Optimization of different parameters, such as the type of solid supports for matrix dispersion and co-column clean-up was carried out. The recoveries of aflatoxins B1, B2, G1 and G2 were 95.4%, 87.3%, 91.5% and 92.6%, respectively, with relative standard deviations ranging from 3.3% to 6.1%. The limits of detection were in the range of 0.10 ng/g (B2, G2) to 0.25 ng/g (B1, G1). In addition, the comparison of the extraction and purification effect of MSPD with immunity affinity column showed that, MSPD is a valid method to analyze aflatoxins in hot chilli products.