2007 Vol. 20, No. 5
To investigate the feasibility of nitrogen and phosphorus recovery from swine waste biogas digester effluent and the effects of pH and NH4+: Mg2+: PO43- molar ratio on its precipitation. Methods Precipitation experiments with swine waste biogas digester effluent were conducted at pH 7.5, 8.0, 8.5, and 9.0 together with NH4+: Mg2+: PO43- molar ratios 1: 0.2: 0.08,1: 1: 1, and 1: 1.5: 1.5. Chemical and X-ray diffraction (XRD) analysis were done to determine the composition of the precipitate. Results The highest removal and recovery of NH4+ and PO43- were achieved at pH 9.0 in each experiment. The elevation of pH to 9.0 alone could decrease the initial PO43- concentration from 42 mg L-1 to 4.7 mg L-1 and 89.2% PO43-recovery was achieved. The pH-molar ratio combination 9.0-1: 1.5:1.5 effected 76.5% NH4+ and 68.5% PO43- recovery. The molar ratio of 1: 1:1 together with pH elevation to 9.0 was determined to be the optimum combination for both NH4+ and PO43-removal as it recovered over 70% and 97% of the initial NH4+ and PO43-, respectively. Conclusions Nitrogen and phosphorus can be recovered from biogas digester effluent as struvite.
To explore the association between polymorphism in the ACE I/D gene and blood pressure-lowering response to hydrochlorothiazide (HCTZ) in 829 patients. Methods HCTZ 12.5 mg was taken once a day for six weeks. The blood pressure reduction and ratio reaching target blood pressure were compared in different ACE genotype groups. Results The reduction in SBP of patients carrying DD was greater than that in other groups carrying Ⅱ or ID (12.2 mmHg versus 5.4 mmHg,12.2 mmHg versus 4.4 mmHg, respectively, P＜0.05). The reduction in MAP of patients carrying DD was also greater than that in other groups carrying Ⅱ or ID (6.9 mmHg versus 3.9 mmHg, 6.9 mmHg versus 3.6 mmHg, respectively, P＜0.05). The ratio reaching target blood pressure in DD groups was significantly higher than that in Ⅱ or ID groups (P＜0.05). The pre-treatment SBP, DD genotype, aldosterone levels entered the multi-linear regression model significantly and might affect the reduction of SBP. The pre-treatment DBP, aldosterone levels, DD genotype entered the multi-linear regression model significantly and might affect the reduction of DBP. The pre-treatment MAP, DD genotype, aldosterone levels entered the multi-linear regression model significantly and might affect the reduction of MAP. Conclusion ACE genotyping is associated with blood pressure-lowering response to HCTZ. Specific genotypes might be associated with the response to specific antihypertensive treatment.
To study the feasibility of enforcing immunization certificate check before children enroll in primary schools or kindergartens in Guizhou Province. Methods Quantitative and qualitative studies were conducted. The multi-stage and cluster sampling approach was adopted for the quantitative part of the study. A questionnaire was designed and 996 children and their keepers were interviewed. Principals, doctors or teachers of the primary schools, directors and child care nurses of kindergarten, and staff of immunization agencies were invited to take part in 12 focus group discussions; meanwhile,face-to-face individual in-depth interviews with 16 officials of the Health, Education and Governmental Departments at various levels were conducted. Results The total number of subjects was 996. 16.7% of the children in the study completed all the procedures of the National Immunization Programme. 34.3% of them had immunization certificates while the remainder 44.7%registered in immunization agencies. Factors, including the migrant children, doubt about vaccine efficiency, mother's occupation and educational background, knowledge of the National Immunization Programme on targeted vaccines, played an important role in obtaining or not immunization certificates. 95% of the keepers interviewed thought the immunization certificates were useful; 94.8% of them considered the check was critical while only 3.6% of them thought it unnecessary. The first reason from those who found it unnecessary was that they feared that repeated immunization might affect their children's health.The second reason was the cost of immunization, which some of them could not afford to pay. However, the Health Department expressed a favorable attitude to the checking scheme. Though the Education Department agreed that the scheme was essential, they worried that it would affect the enrollment rate. Conclusion In spite of the difficulty in administering immunization certificate check, the effort would be rewarding for raising the immunization coverage rate among the children in Guizhou Province.
To evaluate the correlation between the β-fibrinogen gene-455G/A polymorphism and cerebral infarction in Chinese population by means of meta-analysis. Methods Genetic association studies on evaluating the β-fibrinogen gene -455G/A polymorphism and cerebral infarction involving Chinese population published before December 2005 were collected from database of PubMed, EMBASE, and CNKI. All the data in literature were abstracted based on the defined selection criteria by two independent investigators. Publication bias was tested by funnel plot and the odd ratios of all studies were combined dependent on the result of heterogeneity test among the individual studies. The software Review Manager (Version 4.2) was used for meta-analysis. Results Eleven studies including 1405 patients and 1600 controls met the selection criteria.There was no publication bias in 11 reviewed studies. Heterogeneity test of reviewed studies showed statistically significant differences (x2=24.58, P=0.006) among the ORs of individual studies. The combined OR of 11 studies of susceptibility to cerebral infarction in -455A allele carriers compared with the -455G/G wild homozygotes was 1.33 (95%CI 1.04-1.71, P=0.02).In the patients with cerebral infarction in 6 studies, the summarized average plasma fibrinogen level of allele A carrier was 0.29g/L (95%CI 0.14-0.44, P=0.0002) higher than that of -455G/G homozygous ones. Conclusions β-fibrinogen gene -455G/A polymorphism might contribute to susceptibility of cerebral infarction in Chinese population; allele A increases the individual susceptibility to the disease.
To introduce synergetic inactivation of microorganisms in drinking water by short-term free chlorination for less than 15 minutes followed by monochloramination. Methods Indicator microorganisms such as Escherichia coli,Staphylococcus aureus, Candida albicans, and spores of Bacillus subtilis were used to assess the efficiency of sequential chlorination and free chlorination. Results The sequential chlorination was more efficient in inactivating these microorganisms than free chlorination, indicating that synergy was provided by free chlorine and monochloramine. Ammonia addition time, temperature and pH had influences on this synergy. Conclusion The possible mechanism of this synergy might involve three aspects: free chlorine causing sublethal injury to microorganisms and monochloramine further inactivating them; different ability of free chlorine and monochloramine to penetrate and inactivate microorganism congeries; and higher concentration of residual chlorine in sequential chlorination than in free chlorination.
To evaluate whether the clustering of risk factors, both environmental and genetic, increases the risk of essential hypertension (EH) and the accumulation of risk factors influences the blood pressure level in normotensives. Methods On the basis of a prevalence survey, 501 subjects of Mongolian ethnicity (243hypertensives and 258 normotensives) who were not related to each other were selected to conduct a case-control study.All subjects were interviewed with questionnaires and their blood specimens were collected. Renin gene insertion/deletion (I/D) polymorphism, a new genetic marker, was genotyped with PCR and polyacrylamide gel electrophoresis. Results Overweight, alcohol consumption, and renin gene I/D polymorphism were significant risk factors of EH (P＜0.05). The odds ratios (OR) for the number of risk factors were 2.39 (95%CI: 0.98-6.74) for one risk factor, 5.03 (95%CI: 2.06-14.18) for two, and 6.09 (95%CI: 1.85-22.38) for three respectively after adjusting for age and sex. In normotensives, age- and sex-adjusted mean blood pressures increased with more accumulation of risk factors.However, there were no significant differences among the different blood pressure levels according to the number of risk factors (P＞0.05). Conclusion Overweight, alcohol consumption, and renin gene I/D polymorphism are risk factors of EH in the Mongolian ethnic population of China. The accumulation of the risk factors causes a sharp increase of the risk of EH.
To establish a fast and sensitive method for the detection of 8-hydroxy-2'-deoxyguanosine (8-OHdG) in precision-cut rat liver slices by HPLC-MS/MS and to investigate isoniazid (INH) -induced oxidative DNA damage. Methods Precision-cut liver slices (300 μm) were prepared from male rats, and incubated with INH (0.018 mol/L) for 2 h after 1 h preincubation. DNA in the slices was extracted and digested into free nucleosides at 37℃. The samples were injected into HPLC-MS/MS after the proteins were removed. The level of oxidative DNA damage was estimated using the ratio of 8-OHdG to deoxyguanosine (dG). Results The limit of detection of 8-OHdG was 1 ng/mL (S/N=3) and the intra-assay relative standard variation was 3.38% when one transition 284.3/168.4 was used as a quantifier and another two transitions 284.3/140.2,306.1/190.2 as qualifiers. 8-OHdG and dG were well separated, as indicated by elution at 10.02 and 7.37 min, respectively. INH significantly increased the ratio of 8-OHdG to dG in rat liver slices (P＜0.05). Conclusion 8-OHdG in precision-cut liver slices could be sensitively determined by HPLC-MS/MS. HPLC-MS/MS coupled with precision-cut tissue slices is a fast and reliable analytical technique to evaluate oxidative DNA damage of target tissues caused by procarcinogens and cytotoxins.
To study the adsorption of 5-Amino-2-chlorotoluene-4-sulfonic (CLT) and chlorhydric (HCl) acids from wastewater by weakly basic resin.Methods The kinetics and isotherm were studied. Thermodynamic parameters for the adsorption of acids were calculated and discussed.Results The adsorption of CLT and HCl acids followed Langmuir isotherm and the first-order kinetics model.Conclusion The adsorptive affinity of the two acids on D301R is in the order of CLT acid ＞ HCl acid. CLT and HCl acids can be separated.
During present investigation the data of a laboratory-scale anoxic sulfide oxidizing (ASO) reactor were used in a neural network system to predict its performance.Methods Five uncorrelated components of the influent wastewater were used as the artificial neural network model input to predict the output of the effluent using back-propagation and general regression algorithms. The best prediction performance is achieved when the data are preprocessed using principal components analysis (PCA) before they are fed to a back propagated neural network.Results Within the range of experimental conditions tested,it was concluded that the ANN model gave predictable results for nitrite removal from wastewater through ASO process. The model did not predict the formation of suffate to an acceptable manner.Conclusion Apart from experimentation,ANN model can help to simulate the results of such experiments in finding the best optimal choice for ASO based denitrification. Together with wastewater collection and the use of improved treatment systems and new technologies,better control of wastewater treatment plant (WTP) can lead to more effective maneuvers by its operators and,as a consequence,better effluent quality.
To identify the direct causes of drug relapse and abstainers' demand,and to develop programs for the prevention of dmg relapse.Methods Abstainers in a Compulsive Detoxification Center in Wuhan City,capital of Hubei Province were randomly selected. An investigation on the direct causes of drug relapse and abstainers' demands was conducted with multiple-choice questionnaires and face to face interviews. Data were analyzed with SPSS 12.0.Results The direct causes leading to drug relapse included:temptation to use drug again by themselves or by their drug mates,seeking pleasure and ecstasy from drug use,relatively well off living,mental stress,irritation,demoralization,family conflicts,unemployment,feeling distrusted by the family,lack of care and love from the family,and discrimination by others.abstainers' demands after detoxification and returning to the society included:care and support from the family,employment assistance,changing living environment,understanding by others,support from the society,and keeping far away from drugs.Conclusions Environmental factors are the direct causes of drug relapse,and negative irritation is its predisposing causes. Leaving former residence,more care and help given by both the family and the society and raising their overall quality of life are the demands of abstainers.
To investigate reductive dechlorination of 4-chlorophenol (4-CP) by nanoscale Fe0 under different conditions.Methods Nanoscale Fe0 was synthesized by using reductive method. 4-CP and its intermediate products were analyzed by HPLC. Chlorine ion was quantified with DX-100 ion chromatograph. Nano-iron particles were observed under a FEI Quanta 200 FEG environmental scanning electron microscope (ESEM).Results The size of the particles was in the range of 10-100 nm. The nano-iron particles could reduce 4-CP effectively. The initial concentration of 4-CP increased with the decrease of the relative degradation rate,whereas the reduced amount of 4-CP increased. Temperature could influence both the dechlorination rate and the reaction pathway. Moreover,the stability and durability of nanoscale Fe0 was evaluated through batch studies over extended periods of time.Conclusion The nanoscale Fe0 can be used for sustainable treatment of contaminants in groundwater.
The wetland at Dalian Bay in the Northeast of China has been polluted by oil severely. The effect of various microbes and operation parameters on the bioremediation of oil-polluted wetlands at Dalian Bay was investigated and reported previously. In the study,other operation conditions related to the status of medium were investigated via statistical experimental design and analysis and a necessary information is involved to use micro-technology in the application.Methods The method used involved the direct inoculation of selected bacteria,which were capable of degrading oil. The operation conditions were further optimized and evaluated by gravimetrical assay.Results The optimal pH and temperature for the studied bacteria to degrade the existing oil pollutants were established as pH 8.0 and 27℃. The mixed of various bacteria showed better results in terms of oil degradation than any single one. Among the selected four factors,disturbance,oxidant,nutrients,and biosurfactant,the former two contributed more impacts on the oil degradation in the early stage of process,while the latter two became the limiting factors in the late stage. Three sets of optimal conditions were obtained for each individual stage,but no one was suitable for the overall process.Conclusion The study demonstrated the technical feasibility of using direct inoculation into the contaminated soil samples to remove oil pollutants. It suggested that the operation conditions should be monitored and adjusted during the different stages of bio-reactions in the process to achieve the best result of oil degradation.
2007, 20(5): 420-425.
To reduce tobacco consumption and exposure to passive smoking in China.Methods Discussion consisting of 80 focus groups and 35 interviews were held in three rural intervention counties of Jiangxi,Henan,and Sichuan Provinces. Participants came from hospitals,schools,rural areas,and urban areas.Results Tobacco use and exposure to passive smoking were widely prevalent in the investigated schools,hospitals,county towns,and rural areas. Knowledge of the risks for passive smoking on health is lacking,especially in rural areas. Barriers to the control of tobacco use in public places include reluctance of administrators to implement tobacco control policies,lack of consistent policies,difficulties with regulations and enforcement,and reluctance of non-smokers to exercise their right to clean air.Conclusion To curb the current tobacco epidemic in China,tobacco control efforts must focus on reducing exposure to passive smoking. A strategy should be formulated to reduce the factors that contribute to tobacco use and exposure to passive smoking.
2007, 20(5): 426-431.
To investigate the relation between air pollution exposure and preterm birth in Shanghai,China.Methods We examined the effect of ambient air pollution on preterm birth using time-series approach in Shanghai in 2004. This method can eliminate potential confounding by individual risk factors that do not change over a short period of time. Daily numbers of preterm births were obtained from the live birth database maintained by Shanghai Municipal Center of Disease Control and Prevention. We used the generalized additive model (GAM) with penalized splines to analyze the relation between preterm birth,air pollution,and covariates.Results We observed a significant effect of outdoor air pollution only with 8-week exposure before preterm births. An increase of 10 μg/m3 of 8-week average PM10,SO2,NO2,and O3 corresponded to 4.42% (95%CI 1.60%,7.25%),11.89% (95%CI 6.69%,17.09%),5.43% (95%CI 1.78%,9.08%),and 4.63% (95%CI 0.35%,8.91%)increase of preterm birth. We did not find any significant acute effect of outdoor air pollution on preterm birth in the week before birth.Conclusion Ambient air pollution may contribute to the risk of preterm birth in Shanghai. Our analyses also strengthen the rationale for further limiting air pollution level in the city.
Traumatic brain injury (TBI) is one of the leading causes of morbidity and mortality in young people. Inflammatory cytokines play an important part in the pathophysiology of TBI. Recent studies demonstrate that progesterone significantly reduces cerebral edema and enhances functional recovery from TBI and stroke in several animal models. This study was designed to investigate the inhibitory effect of progesterone on inflammatory response after traumatic brain injury. Methods Progesterone was injected intraperitoneally using rats as a model of traumatic brain injury,and Western blot technique was applied to detect the expression of three inflammation-related factors:nuclear factor kappa B p65 (NFk B p65),glial fibrillary acidic protein (GFAP),and tumor necrosis factor-α (TNF-α). The water content of injured brain was also examined. A neurological severity score was recorded to evaluate the effect of progesterone on neurodeficit recovery. Results NFk B p65,GFAP,and TNF-α were increased in all injured animals. In rats treated with progesterone,the expression level of NFkB p65 and TNF-α were reduced significantly in comparison with vehicle-treated rats. However,progesterone did not alter the expression of GFAP in the injured rats. Progesterone also reduced the water content of injured brain and the lesion volume. In addition,progesterone-treated injured rats showed significant improvements in the Neurological Severity Score test,compared with vehicle-treated ones.Conclusions Progesterone inhibits the inflammatory response after experimental traumatic brain injury and mitigates the severity of brain damage.
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