Bacterially mediated release and mobilization of As/Fe coupled to nitrate reduction in a sediment environment.

Metal-reducing bacteria play an important role in the release and mobilization of arsenic from sediments into groundwater. This study aimed to investigate the influence of nitrate on arsenic bio-release. Microcosm experiments consisting of high arsenic sediments and indigenous bacterium Bacillus sp. D2201 were conducted and the effects of nitrate on the mobilization of As/Fe determined. The results show arsenic release is triggered by iron reduction, which is regulated by nitrate. Increasing the nitrate concentration from 0 to 1 and 3 mM decreased Fe(III) reduction by 62.5% and 16.9% and decreased As(V) bio-release by 41.5% and 85.5%, respectively. Moreover, the results of step-wise Wenzel sequential extractions indicate nitrate addition prevents the transformation of poorly crystalline iron oxides to well crystalline iron oxides. Overall, nitrate appears to have a dual effect, inhibiting both iron reduction and arsenic release by incubation strain D2201. This study offers new insights regarding the biogeochemistry of arsenic in groundwater systems.

[Effects of SPR periodontal basic therapy on cervical crevicular fluid C-reactive protein in patients with chronic periodontitis].

PURPOSE: To investigate the effect of SPR periodontal basic treatment on periodontal inflammation control and inflammation index C-reactive protein in gingival crevicular fluid in patients with chronic periodontitis. METHODS: Eighty patients with chronic periodontitis in the pre-clinical trial population were included in this study for subgroup analysis. Repeated measures analysis of variance was used to compare the changes of periodontal index (including average probing depth, clinical adhesion level, and sulcus bleeding index) and gingival crevicular fluid C-reactive protein (CRP) between the SPR treatment group and the control group before treatment and 1 month and 3 months after treatment. Then difference between the two groups was analyzed with SPSS software package. RESULTS: After treatment with different basic treatments, the periodontal indexes SBI, PD, and CAL were significantly decreased compared with those before treatment, and there was significant difference in gingival crevicular fluid CRP, but there was no significant difference between the two groups. The periodontal index of SBI, PD, and CAL in the control group was gradually increased after 3 months and was not significantly different from that before treatment. The improvement of clinical indicators in the experimental group was more obvious and there was significant difference. CRP in the gingival crevicular fluid of the experimental group and the control group were decreased after a period of periodontal treatment, and there was significant difference before and after treatment. There was also a significant difference in CRP between the experimental group and the control group 3 months after treatment (P<0.01). However, CRP in the gingival crevicular fluid gradually increased in the control group after 3 months, and there was no significant difference between the two groups. CONCLUSIONS: Complete SPR periodontal therapy can control chronic periodontitis effectively, reduce CPR of gingival crevicular fluid, and reduce the systemic inflammatory status of patients. This may have a positive impact on the control of risk factors in patients with coronary heart disease.

[Prevention of endodontic interappointment emergencies after one-visit root canal therapy on deciduous teeth with METAPEX].

PURPOSE: To evaluate the clinical effect of calcium hydroxide-iodoform (METAPEX) in one-visit root canal therapy on deciduous teeth and the prevention of endodontic interappointment emergencies (EIAE). METHODS: Two hundred and thirty-eight deciduous anterior and molar teeth from 178 patients were randomly divided into two groups treated with one-visit root canal therapy of METAPEX (experimental group) and zinc oxide eugenol paste (control group). The data was analyzed by Chi-square text with the SPSS14.0 software package. RESULTS: The rate of EIAE after one-visit root canal therapy in the experimental group was significantly lower than in the control group (P<0.05). CONCLUSION: The METAPEX could reduce the occurrence rate of EIAE in the one-visit root canal therapy on deciduous teeth.

[The relationship between the infant nursing bottle caries and the feeding patterns, oral health behavior and parents' oral health information].

PURPOSE: To investigate the relationship between the infant nursing bottle caries in city community and the feeding patterns, oral health behavior, parents' oral health information, and to provide scientific basis for future infant nursing bottle caries prevention. METHODS: Three hundred infants aged 6, 7, 12, 18 months in April 2009 in Bai Guan Street Community Hospital Shangyu City were enrolled in this study, nursing bottle caries were examined and recorded. Questionnaires on infant basic data, feeding patterns, oral health behavior, parents' oral health information were asked and recorded in these 300 parents. The relationship was analyzed between the infant nursing bottle caries and the questionnaires by Chi-square test with the SPSS14.0 software package. RESULTS: The infant nursing bottle caries correlated obviously with the habit of sleeping with the nursing bottle or mammary papilla in mouth, and did not correlate with the breast or artificial feeding patterns. The occurrence rate of infant nursing bottle caries was significantly lower in the infants with oral health behavior than those without oral health behavior. After feeding food, more parents feed the infants with little plain boiled water than clean the infant oral cavity with finger cap wet carbasus. 56.7% of parents had no acknowledge of danger of infant nursing bottle caries. CONCLUSION: There is some correlation between the infant nursing bottle caries and the feeding patterns, oral health behavior, parents' oral health information.