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Background: Abdominal adiposity is associated with increased cardiometabolic risk and visceral adipose tissue (VAT) area obtained from computed tomography (CT) is a key anthropometric index. The present study investigated the VAT criteria on cardiometabolic risk factors in a large-scale nationwide Chinese population.Method: A total of 21,772 adults who underwent a low dose chest CT (LDCT) for lung cancer screening at one of 13 health checkup centers throughout China and had complete ancillary health records were evaluated. Abdominal VAT area at the center of L2 vertebra was measured with Mindways quantitative CT software using the existing LDCT dataset. Relevant anthropometric, serum and blood pressure measurements were obtained from the participants’ records. The VAT distribution of the LDCT cohort was age-adjusted using the Chinese national census. Results: The prevalence of metabolic syndrome based on the Chinese national guidelines was 29.5% and 10.5% in men and women respectively. Using ROC curves, the optimum threshold values for VAT area to identify metabolic syndrome were 213 cm2 in men, and 136 cm2 in women. For participants with VAT area above threshold, the odds ratio (95% confidence interval) for metabolic syndrome was 6.15 (5.65, 6.69) and 9.25 (7.58, 11.4) for men and women respectively. A further analysis of population attributable risk showed that VAT above threshold was significantly associated with an increased risk for metabolic syndrome.Conclusion: In this large-scale nationwide population of China, sex-specific threshold values for VAT area measured by CT were established to identify the risk of metabolic syndrome. VAT area is a key anthropometric index of interventions to control cardiometabolic risk.

A novel kind of electrode for determination of ammonium nitrophenylhydroxyamine (Cupferron) was developed via an easy and effective immobilization method using an acid-catalyzed sol-gel technique. The electrode comprised uranyl nitrate (UO2(NO3)2) immobilized by the thin silica sol-gel film on a glassy carbon electrode (GCE). The UO2(NO3)2 retained its good preconcentration characteristic when being doped by the sol-gel film. Cupferron was determined by the direct reduction at the silica sol-gel immobilized UO2(NO3)2 electrode. Moreover its electrochemical behavior was also investigated. The determination conditions for Cupferron were optimized. The UO22+ film electrode still retained high stability after three months. The experimental results show that this method for Cupferron determination possessed good reproducibility and applicability.

A new method is developed for the catalytic oxidation of ascorbic acid (AA) at a graphite-zeolite-modified electrode doped with iron(III) (Fe3+Y/ZCME), in which iron(III) exchanged in zeolite Y can act as catalyst to oxidize AA. First, the electrochemical behavior of iron(III) incorporated in the zeolite Y-modified electrode was studied. The results illustrate that diffusion controls the ferric/ferrous redox process at the Fe3+Y/ZCME. The anodic current of this process increases with the supporting electrolyte concentration of non-size-excluded cation and was suppressed when using size-excluded cation. Second, the catalytic oxidation of AA was explored at Fe3+Y/ZCME. With constant potential amperometric measurements optimal conditions for AA determination were obtained. The working potential was 0.55 V (vs. SCE); the supporting electrolyte was 0.1 M KNO3Or 0.05 M Na2HPO4-KH2PO4buffer solution (pH 6.8). The response current exhibits a linear relationship with the concentration of AA over the range of 1.58×10–6–2.15×10–2 M. When samples of urine, and fruit were analyzed with Fe3+Y/ZCME, we obtained AA recovery of 98–102%, and a relative standard deviation lower than 3%. Meanwhile, interferences from other ions and organic substances were examined.

A method for the determination of the major serotonin metabolite--5-hydroxyindole-3-acetic acid (5-HIAA) in human gastric juice by cyclic voltammetry was described. The measurement conditions were investigated. The potential window was chosen from +0.1 to +0.9 V, the supporting electrolyte was 0.025 M PBS solution (pH 2.0). The method allowed determination in the concentration range from 2.0 x 10(-7) to 2.0 x 10(-5) M and a detection limit of 80 nM. When samples of gastric juice were analyzed with the method, we obtained the mean content of 5-HIAA in the gastric juice. Meanwhile, interference from other ions and substances were examined. The experimental results indicate that the method for the determination of gastric juice samples is successful.