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1.
Article de Chinois | WPRIM | ID: wpr-997251

RÉSUMÉ

OBJECTIVE@#To examine the impact of COVID-19 pandemic on the epidemic status of imported malaria and national malaria control program in China, so as to provide insights into post-elimination malaria surveillance.@*METHODS@#All data pertaining to imported malaria cases were collected from Anhui Province, Hubei Province, Henan Province, Zhejiang Province and Guangxi Zhuang Autonomous Region during the period from January 1, 2018 through December 31, 2021. The number of malaria cases, species of malaria parasites, country where malaria parasite were infected, diagnosis and treatment after returning to China, and response were compared before (from January 1, 2018 to January 22, 2020) and after the COVID-19 pandemic (from January 23, 2020 to December 31, 2021).@*RESULTS@#A total of 2 054 imported malaria cases were reported in Anhui Province, Hubei Province, Henan Province, Zhejiang Province and Guangxi Zhuang Autonomous Region during the period from January 1, 2018 to December 31, 2021, and there were 1 722 cases and 332 cases reported before and after the COVID-19 pandemic, respectively. All cases were reported within one day after definitive diagnosis. The annual mean number of reported malaria cases reduced by 79.30% in Anhui Province, Hubei Province, Henan Province, Zhejiang Province and Guangxi Zhuang Autonomous Region after the COVID-19 pandemic (171 cases) than before the pandemic (826 cases), and the number of monthly reported malaria cases significantly reduced in Anhui Province, Hubei Province, Henan Province, Zhejiang Province and Guangxi Zhuang Autonomous Region since February 2020. There was a significant difference in the constituent ratio of species of malaria parasites among the imported malaria cases in Anhui Province, Hubei Province, Henan Province, Zhejiang Province and Guangxi Zhuang Autonomous Region before and after the COVID-19 pandemic (χ2 = 146.70, P < 0.05), and P. falciparum malaria was predominant before the COVID-19 pandemic (72.30%), while P. ovale malaria (44.28%) was predominant after the COVID-19 pandemic, followed by P. falciparum malaria (37.65%). There was a significant difference in the constituent ratio of country where malaria parasites were infected among imported malaria cases in Anhui Province, Hubei Province, Henan Province, Zhejiang Province and Guangxi Zhuang Autonomous Region before and after the COVID-19 pandemic (χ2 = 13.83, P < 0.05), and the proportion of malaria cases that acquired Plasmodium infections in western Africa reduced after the COVID-19 pandemic that before the pandemic (44.13% vs. 37.95%; χ2 = 4.34, P < 0.05), while the proportion of malaria cases that acquired Plasmodium infections in eastern Africa increased after the COVID-19 pandemic that before the pandemic (9.58% vs. 15.36%; χ2 = 9.88, P = 0.02). The proportion of completing case investigation within 3 days was significantly lower after the COVID-19 pandemic than before the pandemic (96.69% vs. 98.32%; χ2= 3.87, P < 0.05), while the proportion of finishing foci investigation and response within 7 days was significantly higher after the COVID-19 pandemic than before the pandemic (100.00% vs. 98.43%; χ2 = 3.95, P < 0.05).@*CONCLUSIONS@#The number of imported malaria cases remarkably reduced in Anhui Province, Hubei Province, Henan Province, Zhejiang Province and Guangxi Zhuang Autonomous Region of China during the COVID-19 pandemic, with a decreased proportion of completing case investigations within 3 days. The sensitivity of the malaria surveillance-response system requires to be improved to prevent the risk of secondary transmission of malaria due to the sharp increase in the number of imported malaria cases following the change of the COVID-19 containment policy.


Sujet(s)
Humains , Pandémies , Chine/épidémiologie , Incidence , COVID-19/épidémiologie , Paludisme/prévention et contrôle , Paludisme à Plasmodium falciparum/épidémiologie
2.
Zhonghua ganzangbing zazhi ; Zhonghua ganzangbing zazhi;(12): 494-498, 2020.
Article de Chinois | WPRIM | ID: wpr-828954

RÉSUMÉ

To understand the hepatitis C virus (HCV) genotype distribution characteristics in Xinjiang region. 6462 cases with chronic HCV infection that were treated at the First Affiliated Hospital of Xinjiang Medical University from January 2013 to September 2018 were selected, and repeated testers were excluded. A total of 4773 cases with HCV genotypes were efficiently included. PCR-reverse dot hybridization method was used to retrospectively analyze the genotypes distribution. (2) test or F-test was used for intergroup comparison. < 0.05 was considered as statistically significant. Five genotypes were detected in 4 773 samples: genotype 1b 2928 cases (61.3%), genotype 2a 1241 cases (26%), and genotype 3a 375 cases (7.9%), genotype 3b 205 cases (4.3%), and genotype 6a 24 cases (0.5%). Patients were 48.14 ± 13.93 years old. Genotype 1b was mainly detected in all age groups. There were 2 965 cases of Han ethnicity and 1808 cases of 19 ethnic minorities, of which 1798 cases (60.6%) and 1130 cases (62.5%) were genotype 1b, and 235 cases (7.9%) and 345 cases (19.1%) were genotype 3, respectively. Among the ethnic minorities, Uyghur were the predominant, and genotype 6a could be detected; however, no other ethnic groups had detected genotype 6a. There were 704 Uyghur of genotype 1b (62.1%), 269 Uyghur of genotype 3 (23.7%), and 235 Hans of genotype 3 (7.9%). There were 2 413 males and 2 360 females, of which 1 418 males (58.8%), and 1 510 females (64%) were of genotype 1b, and 424 males (17.6%), and 156 females (6.6%) were of genotype 3. There was a statistically significant difference between the gender of patients with genotype 1b and non-genotype 1b ( < 0.05). There was a statistically significant difference in the detection rate of genotype 2a, 3a, 3b, 6a between Han and ethnic minority patients ( < 0.05). HCV genotypes distribution in Xinjiang region is diverse, and is mainly type 1b. An ethnic minority has higher proportion of HCV genotype 3 than that of Han ethnicity. HCV genotypes detection in Xinjiang region enriches the distribution characteristics of HCV genotypes and provides a basis for individualizing treatment for patients in China.


Sujet(s)
Adulte , Femelle , Humains , Mâle , Adulte d'âge moyen , Chine , Ethnies , Génotype , Hepacivirus , Génétique , Hépatite C , Minorités , Études rétrospectives
3.
Chinese Journal of Epidemiology ; (12): 165-169, 2019.
Article de Chinois | WPRIM | ID: wpr-738233

RÉSUMÉ

Objective: To analyze the pathogenic surveillance programs and related factors on bacillary dysentery in Beijing, 2008-2017, to provide evidence for the practices of diagnosis, treatment and prevention of the disease. Methods: Analysis was conducted on surveillance data of bacillary dysentery, collected from the surveillance areas of national bacillary dysentery in Beijing. Shigella positive rate of stool samples were used as the gold standard while detection rate of Shigella, diagnostic accordance rate and resistance were computed on data from the surveillance programs. Chi-square test was used to compare the rates and unconditional logistic regression was used to analyze the related factors of Shigella infection. Results: Both the reported incidence rate on bacillary dysentery and detection rate of Shigella in diarrhea patients showed significantly decreasing trend, from 2008 to 2017. The accordance rate of bacillary dysentery was only 7.80% (111/1 423). Shigella sonnei was the most frequently isolated strain (73.95%, 159/215) followed by Shigella flexnery. Results from the multivariate logistic regression of Shigella positive rate revealed that among those patients who were routine test of stool positive vs. routine test of stool positive (OR=1.863, 95%CI: 1.402-2.475), onset from July to October vs. other months'time (OR=7.271, 95%CI: 4.514-11.709) temperature ≥38 ℃vs. temperature <38 ℃(OR=4.516, 95%CI: 3.369-6.053) and age from 6 to 59 years old vs. other ages (OR=1.617, 95%CI: 1.085-2.410), presenting higher positive detection rates of Shigella from the stool tests. The resistant rates on ampicillin and nalidixic acid were 97.57% (201/206) and 94.90% (186/196), both higher than on other antibiotics. The resistant rates on ciprofloxacin (16.33%, 32/196), ofloxacin (9.57%, 11/115) and on amoxilin (15.05%, 31/206) were relatively low. The resistant rate appeared higher on Shigella flexnery than on Shigella sonnei. The proportion of strains with resistance on 3 more drugs, was 30.00%(21/70). Conclusions: The diagnostic accordance rate of bacillary dysentery in Beijing was low, with severe resistance of Shigella. Our findings suggested that clinicians should take multiple factors into account in their practices about epidemiological history, clinical symptom and testing results for diarrhea patients.


Sujet(s)
Adolescent , Adulte , Enfant , Humains , Adulte d'âge moyen , Jeune adulte , Antibactériens/usage thérapeutique , Pékin/épidémiologie , Chine/épidémiologie , Dysenterie bacillaire/prévention et contrôle , Fèces/microbiologie , Surveillance de la population/méthodes , Surveillance sentinelle , Shigella/isolement et purification , Shigella flexneri/isolement et purification , Shigella sonnei/isolement et purification
4.
Chinese Journal of Epidemiology ; (12): 218-226, 2019.
Article de Chinois | WPRIM | ID: wpr-738243

RÉSUMÉ

Objective: From the economic point of view, this study was to systematically assess the status quo on lung cancer screening in the world and to provide reference for further research and implementation of the programs, in China. Methods: PubMed, EMbase, The Cochrane Library,CNKI and Wanfang Data were searched to gather papers on studies related to economic evaluation regarding lung cancer screening worldwide, from the inception of studies to June 30(th), 2018. Basic characteristics, methods and main results were extracted. Quality of studies was assessed. Cost were converted to Chinese Yuan under the exchange rates from the World Bank. The ratio of incremental cost-effectiveness ratio (ICER) to local GDP per capita were calculated. Results: A total of 23 studies (only 1 randomized controlled trial) were included and the overall quality was accepted. 22 studies were from the developed countries. Nearly half of the studies (11 studies) took 55 years old as the starting age of the screening program. Smoking history was widely applied for the selection of criteria on target populations (18). Low-dose computed tomography (LDCT) was involved in every study used to evaluate the economic effectiveness. Annual (17) and once-life time (7) screening were more common frequencies. 22 studies reported ICERs for LDCT screening, compared to no screening, of which 17 were less than 3 times local GDP per capita, and were considered as cost-effectiveness, according to the WHO's recommendation. 15 and 7 studies reported ICERs for annual and once-life time screening, of which 12 and 7 studies were in favor the results of their cost-effectiveness, respectively. Additionally, the cost-effectiveness of once-lifetime screening was likely to be superior to the annual screening. Differences of cost-effectiveness among the subgroups, by starting age or by the smoking history, might exist. Conclusions: Based on the studies, evidence from the developed countries demonstrated that LDCT screening programs on lung cancer, implemented among populations selected by age and smoking history, generally appeared more cost-effective. Combined with the local situation of health resource, the findings could provide direction for less developed regions/countries lacking of local evidence. Low frequency of LDCT screening for lung cancer could be adopted when budget was limited. Data on starting ages, smoking history and other important components related to the strategy of screening programs, needs to be precisely evaluated under the situation of local population.


Sujet(s)
Humains , Adulte d'âge moyen , Chine , Analyse coût-bénéfice , Dépistage précoce du cancer/méthodes , Tumeurs du poumon/prévention et contrôle , Années de vie ajustées sur la qualité , Essais contrôlés randomisés comme sujet
5.
Chinese Journal of Epidemiology ; (12): 640-645, 2018.
Article de Chinois | WPRIM | ID: wpr-738016

RÉSUMÉ

Objective: To study the relationship between blood pressure level and major risk factors for cardiovascular diseases in adults in China. Methods: A total of 179 347 adults aged ≥18 years were recruited from 298 surveillance points in 31 provinces in China in 2013 through complex multistage stratified sampling. The survey included face to face interview and physical examination to collect information about risk factors, such as smoking, drinking, diet pattern, physical activity, overweight or obesity, and the prevalence of hypertension. The blood pressure was classified into 6 levels (ideal blood pressure, normal blood pressure, normal high blood pressure and hypertension phase Ⅰ, Ⅱ and Ⅲ). The relationship between the prevalence or co-prevalence of risk factors for cardiovascular disease and blood pressure was analyzed. Results: The adults with ideal blood pressure, normal blood pressure, normal high pressure, hypertension phase Ⅰ, Ⅱ and Ⅲ accounted for 36.14%, 22.77%, 16.22%, 16.43%, 5.97% and 2.48%, respectively. Among them, the blood pressure was higher in men, people in Han ethnic group and those married, and the blood pressure was higher in those with older age, lower income level and lower education level, the differences were all significant (P<0.05). Whether taking antihypertensive drug or not, co-prevalence of risk factors influenced the blood pressure levels of both sexes (P<0.05), and the blood pressure levels of those taking no antihypertensive drug was influenced more by the co-prevalence of risk factors. Finally, multiple logistic analysis showed that the risks for high blood pressure in adults with 1, 2 and ≥3 risk factors were 1.36, 1.79 and 2.38 times higher, respectively, than that of the adults without risk factor. Conclusion: The more the risk factors for cardiovascular disease in adults, the higher their blood pressure were. It is necessary to conduct comprehensive behavior intervention targeting ≥ 2 risk factors for the better control of blood pressure in general population.


Sujet(s)
Adolescent , Adulte , Femelle , Humains , Mâle , Consommation d'alcool/épidémiologie , Antihypertenseurs/usage thérapeutique , Pression sanguine/physiologie , Maladies cardiovasculaires/épidémiologie , Chine/épidémiologie , Régime alimentaire , Hypertension artérielle/épidémiologie , Obésité/épidémiologie , Surpoids , Prévalence , Facteurs de risque , Fumer/épidémiologie , Enquêtes et questionnaires
6.
Chinese Journal of Epidemiology ; (12): 948-953, 2018.
Article de Chinois | WPRIM | ID: wpr-738077

RÉSUMÉ

Objective: To assess the prevalence of HIV infection and related factors in men who have sex with men (MSM) living for ≤5 years in Wenzhou of Zhejiang province. Methods: MSM who were aged ≥16 years, had lived in Wenzhou for ≥3 months and had anal sex and/or oral sex with men in the last 12 months were recruited through respondent-driven sampling (RDS) from February to October in 2015. The MSM recruited completed a questionnaire for the information collection on socio-demographic characteristics, sexual behavior, awareness of HIV and related intervention, mental health status. Blood samples were collected from them for serological detection of HIV and syphilis antibodies. Software SPSS 18.0 was used to analyze HIV infection and related factors. Results: A total of 454 MSM were investigated, 108 of them (23.7%) were HIV positive. There were 267 MSM who lived in Wenzhou for ≤5 years, and 73 of them (27.3%) were HIV positive. Most of them were workers and commercial servants aged ≥25 years with personal monthly income <4 000 yuan and educational level of junior high school or below. According to multiple logistics regression analysis, age of 25-68 years old (OR=12.19, 95%CI: 2.29-65.02), heterosexual behavior in recent 6 months (OR=0.42, 95%CI: 0.18-0.96), believing it was possible to be infected with HIV (OR=0.06, 95%CI: 0.01-0.95), believing it was impossible to be infected with HIV (OR=0.03, 95%CI: 0.01-0.35) and syphilis status (OR=3.32, 95%CI: 1.05-10.52) were the risk factors associated with HIV infection. Conclusion: Compared with MSM who lived in Wenzhou for >5 years, MSM who lived in Wenzhou for ≤5 years had higher HIV infection rate and higher prevalence of risk behavior. It is necessary to conduct targeted intervention among them.


Sujet(s)
Adulte , Sujet âgé , Humains , Mâle , Adulte d'âge moyen , Infections à VIH/épidémiologie , Homosexualité masculine/statistiques et données numériques , Comportement sexuel , Enquêtes et questionnaires
7.
Chinese Journal of Epidemiology ; (12): 966-970, 2018.
Article de Chinois | WPRIM | ID: wpr-738080

RÉSUMÉ

Objective: To understand the survival of HIV/AIDS patients after receiving antiretroviral therapy for 10 year in Henan province and related factors. Methods: The database of national integrated management system of HIV/AIDS was used to collect the basic information and follow-up information of HIV/AIDS patients who received antiretroviral therapy between 2003 and 2005 in Henan province. Software SPSS 23.0 was used to analyze the patients' survival and related factors based on the life-table method and Cox proportional hazards model. Results: Among the 2 448 HIV/AIDS patients who started antiretroviral therapy during 2003-2005, the men accounted for 53.5%, and women accounted for 46.5%. Up to 70.1% of the patients were aged 40-59 years and 95.5% of the patients had blood borne infections. The patients were observed for 10 years after antiviral treatment, and 719 cases died from AIDS related diseases, with a mortality rate of 3.78/100 per year (719/19 010 per year). The cumulative survival rates of patients within 1-year, 3 years, 5 years and 10 years were 0.94, 0.86, 0.78, 0.69 respectively. Compared with the patients aged <40 years, the HRs of the patients aged 40-, 50-, 60- and ≥70 years were 1.417 (95%CI: 0.903-2.222), 1.834 (95%CI: 1.174-2.866), 2.422 (95%CI: 1.539-3.810) and 3.424 (95%CI: 2.053-5.709) respectively. Compared with patients with baseline CD(4+)T lymphocyte >350 unit/ul, the HRs of the patients with CD(4+)T lymphocyte <50 unit/μl, 50-199 unit/ul and 200-350 unit/ul were 7.105 (95%CI: 5.449-9.264), 4.175 (95%CI: 3.249-5.366) and 2.214 (95%CI: 1.691-2.900) respectively. Compared with the women, the HR of the men was 1.480 (95%CI: 1.273-1.172). Compared with the patients who received second line ART therapy, the HR of patients receiving no second line therapy was 11.923 (95%CI: 9.410-15.104). Conclusions: The cumulative survival rate the HIV/AIDS patients after 10 years of antiretroviral therapy reached 0.69 in Henan. Male, old age, low basic CD(4+)T lymphocyte count and receiving no second line therapy were the risk factors for long-term survival of AIDS patients.


Sujet(s)
Adulte , Sujet âgé , Femelle , Humains , Mâle , Adulte d'âge moyen , Syndrome d'immunodéficience acquise , Thérapie antirétrovirale hautement active , Numération des lymphocytes CD4 , Chine/épidémiologie , VIH (Virus de l'Immunodéficience Humaine)/effets des médicaments et des substances chimiques , Infections à VIH/mortalité , Modèles des risques proportionnels , Facteurs de risque , Analyse de survie , Taux de survie
8.
Chinese Journal of Epidemiology ; (12): 1096-1099, 2018.
Article de Chinois | WPRIM | ID: wpr-738104

RÉSUMÉ

Objective: To establish a classified evaluation system for recognizing the levels of influenza epidemics and to explore the new reporting system on influenza epidemics. Methods: The following 3 indicators, including 1) the number of influenza-like illness, 2) positive rate of detection on influenza virus nucleic acids, and 3) the number of influenza outbreaks were chosen to calculate the synthetic index and to classify the grades of evaluation. Results: 209 weeks during 2013-2017 were classified into 5 grades: Grade 1 were 110 weeks (52.63%), Grade 2 were 47 weeks (22.49%), Grade 3 were 44 weeks (21.05%), Grade 4 were 8 weeks (3.83%), and Grade 5 were 0 week. Conclusion: This classified evaluation system provided simple, comprehensive and comparable reference indicators and used for the evaluation on influenza epidemics, also providing suggestions for influenza prevention and control accordingly.


Sujet(s)
Humains , Pékin/épidémiologie , Épidémies de maladies , Épidémies , Grippe humaine/épidémiologie , Surveillance de la population , Maladies virales
9.
International Journal of Radiation Research. 2017; 15 (3): 321-324
de Anglais | IMEMR | ID: emr-189531

RÉSUMÉ

Background: The activity concentrations of natural radionuclides in soil around a coal-fired thermal power plant of northwest China were investigated for assessing the radioactivity level


Materials and Methods: Soil samples were collected around the coal-fired thermal power plant and their radioactivity levels were determined using gamma ray spectrometry. Radiation hazards were assessed by radium equivalent activity [Raeq], air absorbed dose rate [D] and annual effective dose equivalent [AEDE]


Results: The activity concentrations of [226]Ra, [232]Th and [40]K ranged from 24.7 to 89.8, 38.4 to 122.3 and 206.7 to 573.8 Bq kg[-1] with an average of 49.7, 63.5 and 396.3 Bq kg[-1], respectively. The mean Ra[eq] value was less than the recommended limit, while the mean values of D and AEDE were slightly higher than the corresponding world average


Conclusion: The coal-fired thermal power plant enhanced the natural radiation of surrounding soil environment

10.
Zhonghua Yu Fang Yi Xue Za Zhi ; (12): 165-171, 2017.
Article de Chinois | WPRIM | ID: wpr-297360

RÉSUMÉ

To study the effect of iodine deficiency on body weight, food consumption, and food utilization rate of second filial generation Wistar rats.According to the food pattern of a high-iodine deficient population, two types of low-iodine food have been produced using the main crops grown in this area (iodine levels of 50 and 20 μg/kg, respectively). Wistar rats were randomly divided into three groups, normal iodine group (NI group), low-iodine group one (LI group) and low-iodine group two (LII group), using the random number table method and fed diets containing 300, 50, and 20 μg/kg of iodine, respectively. Parental generation rats were fed until they reached reproductive age; first filial generation rats were allocated to the same diet as their mothers. After 3 months of feeding, first filial generation rats gave birth to second filial generation rats; second filial generation rats were allocated to the same diet as their mothers. After feeding for 90, 180, and 270 days, rats were sacrificed. One-way analysis of variance was used to analyze body weight, food intake, and food utilization rate data collected during the time of feeding and blood iodine hormone level, which was determined after sacrifice.The LI and LII groups generally demonstrated decreased activity, slow reaction, and growth retardation compared with the NI group. After 270 days, the urine iodine levels of the LI and LII groups were 1.7 and 0.2 μg/L, respectively, which were significantly lower than the NI group (255.2 μg/L) (0.001). Additionally, the weight of female rats in the LI and LII groups were (288.1±10.5) and (275.7±2.7) g, respectively, which was significantly lower than that of the NI group ((311.0±2.3) g) (0.001). The weight of male rats were (446.0±4.6) and (451.8±19.1) g, respectively, which were significantly lower than that of the NI group ((517.2±7.8) g) (0.001). In the LI and LII groups, food intake of female and male rats after 270 days were (465.0±27.7), (658.4±28.6) and (423.0±13.2), (548.0±18.8) g, respectively, which were significantly lower than that of the NI group ((499.5±21.8), (760.8±33.0) g) (0.001). Moreover, the food utilization rate of female rats in the LI and LII groups was (8.7±0.4)% and (6.0±0.58)%, which was lower than that of the NI group ((11.7±3.5)%) (0.001); similarly, male rats showed rates of (8.9±1.5)% and (6.9±1.31)%, respectively, which were lower than that of the NI group ((13.7±3.0)%) (0.001). After 270 days, the level of T3 in the LI and LII groups were (0.45±0.10) and (0.34±0.15) ng/ml, respectively, which was significantly lower than that of the NI group ((0.91±0.49) ng/ml) (0.01). Moreover, the level of T4 were (69.02±27.87) , (53.18±13.53) ng/ml in LI and LII groups, respectively, which was lower than that of the NI group ((76.69±29.42) ng/ml) (0.05).This study indicated that iodine deficiency induced by a long-term low-iodine diet can cause changes in weight, food intake, and food utilization rate among second filial iodine deficiency rats. More importantly, the iodine content in low-iodine food impacts these parameters.


Sujet(s)
Animaux , Femelle , Mâle , Rats , Poids , Régime alimentaire , Aliments , Iodures , Iode , Répartition aléatoire , Rat Wistar , Glande thyroide , Métabolisme , Thyroxine , Sang , Temps
11.
Article de Chinois | WPRIM | ID: wpr-780997

RÉSUMÉ

Objective:To evaluate resection of submandibular gland through a minimal skin incision under the endoscope. Method:A retrospective analysis of the clinical data from 28 cases of submandibular gland resection by endoscope surgery via subclavian approach, 14 cases of preoperative diagnosis of pleomorphic adenoma, submandibular gland of chronic inflammation in 11 cases, 3 cases of the submandibular gland stone,one case of lymphatic cyst,all cases were evaluated by preoperative imaging or 3 d sonography. Result:All patients' submandibular gland and tumors were resected totally under the endoscope, no open surgery, no surgical complications, and postoperative aesthetic outcome was good, patients were satisfied, pleomorphic adenoma patients were postoperative followed up of 4 to 24 months, and no recurrence. Conclusion:Under the cavity mirror via subclavian path submandibular gland resection is safe and feasible, and has a good cosmetic effect.

12.
International Journal of Environmental Science and Technology. 2010; 7 (2): 235-242
de Anglais | IMEMR | ID: emr-99047

RÉSUMÉ

The adsorption of methyl tert-butyl ether by granular activated carbon was investigated. The experimental data were analyzed using the Freundlich isotherm and the Langmuir isotherm. Although equilibrium data were found to follow Freundlich isotherm model, it were fitted better by the Langmuir model with a maximum adsorption capacity of 204.1 mg/g. The kinetic data obtained at different concentrations were analyzed to predict the constant rate of adsorption using three common kinetic models: pseudo-first-order, pseudo-second-order equation and intraparticle diffusion equation. The pseudo-second-order model was suitable for describing the adsorption kinetics for the removal of methyl tert -butyl ether from aqueous solution onto granular activated carbon. Both the Lagergren first-order rate constant k[1] and pseudo-second-order rate constant k2 decrease with increasing initial concentrations of methyl tert-butyl ether and the intraparticle diffusion rate constant k[p] shows the reverse characteristic. Analysis of sorption data using a boyd plot confirmed that external mass transfer is the main rate-limiting step at the initial stage of adsorption. Results illustrate that granular activated carbon is an effective adsorbent for methyl tert-butyl ether and also provide specific guidance into adsorption of methyl tert-butyl ether on granular activated carbon in contaminated groundwater


Sujet(s)
Adsorption , Diffusion , Carbone
13.
International Journal of Environmental Science and Technology. 2009; 6 (1): 69-76
de Anglais | IMEMR | ID: emr-91331

RÉSUMÉ

A simplified environmental biological model has been developed based on biodegradation kinetics correlation to regulate and optimize wastewater treatment system of activated sludge process. All parameters included in the model are calibrated in accordance with reference data and experimental results and good agreements are achieved between calculated results and reference data or experimental results. The minimum bioreactor volume is used as objective function in the model and errors between optimal minimum volume of the model and each reported result of three references are found to be no more than 8.63% after validation. Comparisons between optimal results and experimental data demonstrate that the deviations are negligible. The optimal minimum volume is 9.21 m3 with the error of 6.40% to the practical bioreactor volume of a pilot treatment system. The environmental biological model has been applied to economically evaluate a former treatment system with native bacterium YZ1 and four operation periods of the pilot system with functional strain Fhhh compared with YZ1, Fhhh possesses higher biodegradation ability in purified terephthalic acid wastewater and a broader economic potential in the field of wastewater treatment


Sujet(s)
Gestion des déchets , Modèles théoriques , Eaux d'égout
14.
EMHJ-Eastern Mediterranean Health Journal. 2007; 13 (1): 6-16
de Anglais | IMEMR | ID: emr-156966

RÉSUMÉ

A central requirement of research involving humans is that people who participate as subjects should do so voluntarily. We argue that disagreements about the effect of offers of compensation on subjects' ability to participate voluntarily are likely to persist and to have high social costs. We propose a novel compensation practice-to pay potential subjects whether or not they participate-and argue that its implementation in some regions, including the Eastern Mediterranean Region, may reduce disagreement and thus mitigate such costs. We outline a research programme for assessing the potential of this practice to reduce costs


Sujet(s)
Humains , Expérimentation humaine/éthique , Personnes se prêtant à la recherche , Pauvreté , Maîtrise des coûts , Consentement libre et éclairé
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