[Temporal and Spatial Variation Characteristics and Driving Factors of Nitrogen of Shallow Groundwater in Hetao Irrigation District].

As an important food production area in the north of China, the Hetao plain is extremely vulnerable to nitrate pollution caused by agricultural production activities and additional factors. Thus, it is of great significance for the environmental protection and rational use of groundwater to detect the current situation of groundwater nitrate pollution, temporal and spatial evolution characteristics, and main influencing factors in the Hetao irrigation district. We selected the Wualte irrigation area as the study area, and the characteristics of temporal and spatial changes in groundwater nitrate concentration and the main influencing factors in this area were explored. We used statistical analysis to analyze the nitrogen content of groundwater in the study area, and the Piper three-line diagram was used to explore the characteristics of chemical composition and evolution; furthermore, we used ion ratio and correlation analysis methods to explore the source of NO3--N in groundwater. The results showed that NO3--N was the main existing form of nitrogen in the Wulate irrigation area, and its concentration varied from 0.01 to 60.00 mg·L-1, with an exceeding standard rate of 10.50%. In terms of time, the characteristic of time change was that the NO3--N concentration in August of groundwater was the highest (average 6.61 mg·L-1), followed by that in October (6.22 mg·L-1) and November (6.25 mg·L-1), and that in March (average value of 1.77 mg·L-1) was the lowest. With the influence of rainfall and irrigation, the NO3--N in the soil was infiltrated into the groundwater, showing the characteristic that wet season and concentrated irrigation periods were higher than those in other periods. Spatially, it appeared as southwest (8.87 mg·L-1)>northwest (4.25 mg·L-1)>east (0.89 mg·L-1), mainly due to the original geological conditions, land use, and domestic waste stacking. In addition, the concentration of NO3--N of groundwater in the study area was closely related to the depth of groundwater and redox conditions but was relatively less affected by the concentration of water chemical ions. Therefore, identifying the temporal and spatial distribution characteristics and main sources of groundwater nitrogen pollution can provide a scientific basis for scientific fertilization, groundwater nitrate pollution control, and water safety.

Effects of long-term treatment with quercetin on cognition and mitochondrial function in a mouse model of Alzheimer's disease.

Amyloid-ß (Aß)-induced mitochondrial dysfunction has been recognized as a prominent, early event in Alzheimer's disease (AD). Therefore, therapeutics targeted to improve mitochondrial function could be beneficial. Quercetin, a bioflavanoid, has been reported to have potent neuro-protective effects, but its preventive effects on Aß-induced mitochondrial dysfunction and cognitive impairment have not been well characterised. Three-month-old APPswe/PS1dE9 transgenic mice were randomly assigned to a vehicle group, two quercetin (either 20 or 40 mg kg(-1) day(-1)) groups, or an Aricept (2 mg kg(-1) day(-1)) group. After 16 weeks of treatment, we observed beneficial effects of quercetin (40 mg kg(-1) day(-1)), including lessening learning and memory deficits, reducing scattered senile plaques, and ameliorating mitochondrial dysfunction, as evidenced by restoration of mitochondrial membrane potential, reactive oxygen species and ATP levels in mitochondria isolated from the hippocampus compared to control. Furthermore, the AMP-activated protein kinase (AMPK) activity significantly increased in the quercetin-treated (40 mg kg(-1) day(-1)) group. These findings suggest that a reduction in plaque burden and mitochondrial dysfunction through the activation of AMPK may be one of the mechanisms by which quercetin improves cognitive functioning in the APPswe/PS1dE9 transgenic mouse model of AD.

Neuroprotective effects of ultra-low-molecular-weight heparin in vitro and vivo models of ischemic injury.

This study was conducted to demonstrate ultra-low-molecular-weight heparin's neuroprotective effects on ischemic injury both in vivo and in vitro studies. In vitro, the effect of ultra-low-molecular-weight heparin was tested in cultured PC12 cells exposed to Earle's solution containing sodium dithionite, to identify its neuroprotection to PC12 cells damaged by oxygen-glucose deprivation (OGD). The cell injury was detected by the tetrazolium salt 3-(4,5-dimethyl-2-thiazolyl)-2,5 diphenyl-2H tetrazolium bromide (MTT) assay. In vivo, male Wistar rats with middle cerebral artery occlusion were evaluated for infarct volume followed by the treatment with ultra-low-molecular-weight heparin. The results in vitro showed that ultra-low-molecular-weight heparin significantly inhibited PC12 cells damage induced by OGD. Results in vivo showed that vein injection of Ultra-Low-molecular-weight heparin at doses of 0.5 and 1.0 mg/kg exerted significant neuroprotective effects on rats with focal cerebral ischemic injury by significantly reducing the infarct volume compared with the injury group. All the findings suggest that ultra-low-molecular-weight heparin might act as a neuroprotective agent useful in the treatment of cerebral ischemia.

[Analysis of the infection status and the drug resistance of mycoplasma and chlamydiae in genitourinary tracts of children with suspected nongonococcal urethritis].

OBJECTIVE: To investigate the infection and the drug resistance status of mycoplasma and chlamydiae in genitourinary tracts of children with suspected nongonococcal urethritis (NGU) and provide information for clinical rational administration of antimicrobial agents. METHODS: Samples of genitourinary tract secretion from 146 children who were suspected of having nongonococcal urethritis or colpitis were collected and tested for mycoplasma via culture and for chlamydia with antigen detection. Meanwhile, susceptibility test was carried out on the samples which were positive in mycoplasma cultivation. Chlamydia antigen was detected by the polymer conjugate-enhanced (PCE) indirect enzyme immunoassay (EIA) (IDEIA PCE Chlamydia; DAKO). The mycoplasma culture medium was produced by Nanjing Liming Biological Products Co,. Ltd. Antibiotics used for susceptibility test were erythromycin, roxithromycin, josamycin, leucomycin, meleumycin, rovamycin, azithromycin, clarithromycin, cycloate erythromycin, and clindamycin. RESULTS: Fifteen samples were positive for Chlamydia trachomatis (Ct) by antigen detection (10.3%), 82 samples were positive in mycoplasma cultivation (56.2%), and among the 82 samples, 58 were positive for Ureaplasma urealyticum (Uu, 39.7%), 9 were positive for Mycoplasma hominis (Mh, 6.2%), and 15 were positive for Uu and Mh (10.3%). Of all the samples, 4 were positive for both Uu and Ct (2.7%). The rates of drug resistance of the 10 commonly used antibiotics were as follows: erythromycin 32.9%, roxithromycin 41.5%, josamycin 19.5%, leucomycin 22.0%, meleumycin 28.0%, rovamycin 30.5%, azithromycin 37.8%, clarithromycin 26.8%, davercin 24.4%, and clindamycin 26.8%, respectively. The results indicated that drug resistance rates of josamycin and leucomycin were the lowest, and the rates of roxithromycin and azithromycin were the highest. CONCLUSIONS: The infection rates of mycoplasma and chlamydia in children suspected NGU were high. Mycoplasma showed drug resistance to a different degree to 10 common antibiotics. The results of chemosensitivity showed that josamycin had the highest susceptibility rate.

[Impact of pH on the generation of COD, phosphorous and ammonia-nitrogen during the anaerobic fermentation of excess activated sludge].

There are mainly two kinds of sludge in the municipal wastewater treatment plant, i. e. , primary and secondary sludge. This study investigated the effect of pH, ranging from 4.0-11.0, on hydrolysis in terms of soluble chemical oxygen demand (SCOD) production in the anaerobic solubilization of excess activated sludge at 20-22 degrees C. It was found that when the value of pH was 8.0-10.0, the production quantity of SCOD were higher than pH = 5.0-7.0. Especially when the pH was 10.0 or 11.0, the value of SCOD was almost 10 times of pH = 6.0 during the whole fermentation of 20 days. And volatile fatty acids (VFA) production on the 8th day under alkaline condition was higher than that under acidic condition.

[A new chromone glycoside from Cassia siamea lam].

AIM: To study the chemical constituents of the stem of Cassia siamea. METHODS: The compounds were isolated by chromatography on silica gel, and identified on the basis of spectral analysis. RESULTS: Five compounds were isolated and identified as: beta-sitosterol (I), sucrose (II), n-octacosanol (III), 2-methyl-5-(2'-hydroxypropyl)-7-hydroxy-chromone-2'-O-beta-D-glucopyranoside (IV) and piceatannol (V). CONCLUSION: Compound IV is a new compound. Compounds II, III and V were obtained from this plant for the first time.