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Objective@#To analyze the related factors of the onset of vasovagal syncope (VVS) in children, and to provide basis for the early prevention, early diagnosis and early treatment of VVS.@*Methods@#A total of 126 children with syncope admitted to Department of Pediatric Cardiology, Second Hospital of Lanzhou University from October 2018 to September 2019 were invited in the study. Totally 73 cases of children diagnosed with VVS by HUTT were selected as VVS group, and 53 HUTT negative children were selected as control group. Related factors were retrospectively investigated, and risk factors for VVS were analyzed by univariate and multivariate regression.@*Results@#The VVS group showed statistically significant difference in age distribution with the control group ( χ 2=19.22, P <0.05). The VVS group showed statistically significant differences of proportion in family history, syncope history, prolonged standing, electrocardiogram abnormalities, and vitamin D deficiency (43.84%，31.51%，47.95%，34.25%， 30.14 %) compared with the control group (15.09%，13.21%，20.75%，15.09%，9.43%) ( χ 2=11.71,5.67,9.79,5.83,7.82, P < 0.05 ). Multivariate Logistic regression analysis showed that age and family historywere risk factors for VVS( χ 2=3.13, 11.06, P < 0.05 ).@*Conclusion@#Age and family history may be risk factors for the onset of VVS. Active attention should be paid to the high risk factors of child patient, early identification and diagnosis can prevent the occurrence and development of VVS in children.
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BACKGROUND: The development of clean or novel alternative energy has become a global trend that will shape the future of energy. In the present study, 3 microbial strains with different oxygen requirements, including Clostridium acetobutylicum ATCC 824, Enterobacter cloacae ATCC 13047 and Kluyveromyces marxianus 15D, were used to construct a hydrogen production system that was composed of a mixed aerobic-facultative anaerobic-anaerobic consortium. The effects of metal ions, organic acids and carbohydrate substrates on this system were analyzed and compared using electrochemical and kinetic assays. It was then tested using small-scale experiments to evaluate its ability to convert starch in 5 L of organic wastewater into hydrogen. For the one-step biohydrogen production experiment, H1 medium (nutrient broth and potato dextrose broth) was mixed directly with GAM broth to generate H2 medium (H1 medium and GAM broth). Finally, Clostridium acetobutylicum ATCC 824, Enterobacter cloacae ATCC 13047 and Kluyveromyces marxianus 15D of three species microbial co-culture to produce hydrogen under anaerobic conditions. For the two-step biohydrogen production experiment, the H1 medium, after cultured the microbial strains Enterobacter cloacae ATCC 13047 and Kluyveromyces marxianus 15D, was centrifuged to remove the microbial cells and then mixed with GAM broth (H2 medium). Afterward, the bacterial strain Clostridium acetobutylicum ATCC 824 was inoculated into the H2 medium to produce hydrogen by anaerobic fermentation. RESULTS: The experimental results demonstrated that the optimum conditions for the small-scale fermentative hydrogen production system were at pH 7.0, 35°C, a mixed medium, including H1 medium and H2 medium with 0.50 mol/L ferrous chloride, 0.50 mol/L magnesium sulfate, 0.50 mol/L potassium chloride, 1% w/v citric acid, 5% w/v fructose and 5% w/v glucose. The overall hydrogen production efficiency in the shake flask fermentation group was 33.7 mL/h-1.L-1, and those the two-step and the one-step processes of the small-scale fermentative hydrogen production system were 41.2 mLVh-1.L-1 and 35.1 mL/h-1.L-1, respectively. CONCLUSION: Therefore, the results indicate that the hydrogen production efficiency of the two-step process is higher than that of the one-step process.