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1.
Hong Kong Med J ; 24(3): 238-244, 2018 06.
Artigo em Inglês | MEDLINE | ID: mdl-29807948

RESUMO

INTRODUCTION: Children in Hong Kong are generally hospitalised for 1 to 2 weeks after hypospadias repairs. In July 2013, we introduced a new service model that featured an enhanced recovery pathway and a dedicated surgical team responsible for all perioperative services. In this study, we investigated the outcomes of hypospadias repair after the introduction of the new service model. METHODS: We conducted a retrospective study on consecutive children who underwent primary hypospadias repair from January 2006 to August 2016, comparing patients under the old service with those under the new service. Outcome measures included early morbidity, operative success, and completion of enhanced recovery pathway. RESULTS: The old service and new service cohorts comprised 176 and 126 cases, respectively. There was no difference between the two cohorts in types of hypospadias and surgical procedures performed. The median hospital stay was 2 days in the new service cohort compared with 10 days in the old service cohort (P<0.001). Patients experienced less early morbidity (5.6% vs 15.9%; P=0.006) and had a lower operative failure rate (20.2% vs 44.2%; P<0.001) under the new service than the old service. Multivariable analysis revealed that the new service significantly reduced the odds of early morbidity (odds ratio=0.35, 95% confidence interval=0.15-0.85; P=0.02) and operative failure (odds ratio=0.32, 95% confidence interval=0.17-0.59; P<0.001) in comparison with the old service. Of the new service cohort, 111(88.1%) patients successfully completed the enhanced recovery pathway. CONCLUSIONS: The enhanced recovery pathway can be implemented safely and effectively to primary hypospadias repair. A dedicated surgical team may play an important role in successful implementation of the enhanced recovery pathway and optimisation of surgical outcomes.


Assuntos
Hipospadia/cirurgia , Tempo de Internação/estatística & dados numéricos , Assistência Perioperatória/métodos , Procedimentos de Cirurgia Plástica , Pré-Escolar , Procedimentos Clínicos , Hong Kong , Humanos , Lactente , Modelos Logísticos , Masculino , Análise Multivariada , Complicações Pós-Operatórias/etiologia , Procedimentos de Cirurgia Plástica/efeitos adversos , Estudos Retrospectivos , Falha de Tratamento
5.
Hong Kong Med J ; 22(5): 454-63, 2016 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-27516568

RESUMO

OBJECTIVE: To investigate the prevalence of lower urinary tract symptoms in adolescents and the effects of psychotropic substance use. METHODS: This was a population-based cross-sectional survey using a validated questionnaire in students from 45 secondary schools in Hong Kong randomly selected over the period of January 2012 to January 2014. A total of 11 938 secondary school students (response rate, 74.6%) completed and returned a questionnaire that was eligible for analysis. Individual lower urinary tract symptoms and history of psychotropic substance abuse were documented. RESULTS: In this study, 11 617 non-substance abusers were regarded as control subjects and 321 (2.7%) were psychotropic substance users. Among the control subjects, 2106 (18.5%) had experienced at least one lower urinary tract symptom with urinary frequency being the most prevalent symptom (10.2%). Females had more daytime urinary incontinence (P<0.001) and males had more voiding symptoms (P=0.01). Prevalence of lower urinary tract symptoms increased with age from 13.9% to 25.8% towards young adulthood and age of ≥18 years (P<0.001). Among the substance users, ketamine was most commonly abused. Substance users had significantly more lower urinary tract symptoms than control subjects (P<0.001). In multivariate analysis, increasing age and psychotropic substance abuse increased the odds for lower urinary tract symptoms. Non-ketamine substance users and ketamine users were respectively 2.8-fold (95% confidence interval, 2.0-3.9) and 6.2-fold (4.1-9.1) more likely than control subjects to develop lower urinary tract symptoms. Females (odds ratio=9.9; 95% confidence interval, 5.4-18.2) were more likely to develop lower urinary tract symptoms than males (4.2; 2.5-7.1) when ketamine was abused. CONCLUSIONS: Lower urinary tract symptoms are prevalent in the general adolescent population. It is important to obtain an accurate history regarding psychotropic substance use when treating teenagers with lower urinary tract symptoms.


Assuntos
Ketamina/administração & dosagem , Sintomas do Trato Urinário Inferior/epidemiologia , Psicotrópicos/administração & dosagem , Transtornos Relacionados ao Uso de Substâncias/epidemiologia , Adolescente , Fatores Etários , Criança , Estudos Transversais , Feminino , Hong Kong/epidemiologia , Humanos , Masculino , Análise Multivariada , Prevalência , Fatores de Risco , Fatores Sexuais , Inquéritos e Questionários
6.
Environ Monit Assess ; 188(7): 404, 2016 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-27295186

RESUMO

The present study deals with possible contamination of the soil by metal ions which have been affecting the environment. The concentrations of metal ions in 14 borehole samples were studied using the ICP-OES standard method. The degree of contamination was determined on the basis of single element pollution index (SEPI), combined pollution index (CPI), soil enrichment factor (SEF), and geo-accumulation index (Igeo). Geo-accumulation indices and contamination factors indicated moderate to strong contaminations for eight boreholes (BL-1, BL-2, BL-6, BL-8, BL-9, BL-10, BL-12, and BL-13) while the rest were extremely contaminated. Among all the boreholes, BL-3 and BL-11 demonstrated the highest level of Cd(II) and Pb(II) which were found the most polluted sites. The level of metal contamination was also compared with other countries. The development, variation, and limitations regarding the regulations of soil and groundwater contamination can be provided as a helpful guidance for the risk assessment of metal ions in developing countries.


Assuntos
Monitoramento Ambiental/métodos , Metais Pesados/análise , Poluentes do Solo/análise , Poluição Ambiental/análise , Água Subterrânea/análise , Solo/química
8.
J Clin Pediatr Dent ; 39(2): 105-8, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25823479

RESUMO

OBJECTIVE: Pregnancy gingivitis and early childhood caries remain prevalent in Hong Kong. The aim of this study was to assess pregnant women's knowledge and beliefs related to pregnancy gingivitis and children's oral health. STUDY DESIGN: An outreach survey was carried out in a clinic that provided antenatal examination. A written oral health questionnaire related to pregnancy gingivitis and early childhood caries was administered to pregnant women. Of the 106 pregnant women who enrolled in the study, 100 completed the questionnaires. RESULTS: Among the 100 subjects, only 39% correctly identified that hormonal changes contribute to pregnancy gingivitis. Only 36% identified red and swollen gums as signs of gingivitis. Furthermore, 53% of the surveyed pregnant women were not sure about the amount of toothpaste to administer to a child aged 18 months to 5 years. Almost 50% assumed that a replanted avulsed tooth would probably not survive within a short extra-alveolar period of less than 60 minutes. CONCLUSION: Prenatal women generally lack knowledge of a common oral disease that occurs during pregnancy and of what constitutes adequate oral health care for children. Oral health care education should be implemented as part of a prenatal care program.


Assuntos
Atitude Frente a Saúde , Gengivite/complicações , Conhecimentos, Atitudes e Prática em Saúde , Saúde Bucal , Complicações na Gravidez , Gestantes , Adulto , Cariostáticos/administração & dosagem , Pré-Escolar , Assistência Odontológica/psicologia , Cárie Dentária/psicologia , Feminino , Fluoretos/administração & dosagem , Humanos , Lactente , Gravidez , Avulsão Dentária/psicologia , Reimplante Dentário/psicologia , Escovação Dentária/psicologia , Cremes Dentais/administração & dosagem
9.
Pediatr Surg Int ; 30(1): 107-11, 2014 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-24085513

RESUMO

AIM OF THE STUDY: Anatomical variations on venous drainage in varicoceles are under-reported. We report our experience in scrotal antegrade sclerotherapy (SAS) for adolescent varicoceles. METHODS: Since 2011, 15 consecutive boys with left varicoceles were recruited. Under general anaesthesia, a 5-mm transverse incision was made at scrotal neck, testicular vein was cannulated at pampiniform plexus with venogram performed. Foam sclerosant by mixing sodium tetradecyl sulphate (STS), Lipiodol(®) and air was slowly injected under fluoroscopy. Postoperatively the patients were followed-up for varicocele grading, testicular size, and complications. MAIN RESULTS: Median age at operation was 14 (10-19) years. 80 % had grade three varicoceles, 33.3 % had smaller left testis before operation. Intra-operative venogram showed three different anatomical variations. Group I: eleven patients (73.3 %) had single distinct internal spermatic vein; Group II: two patients demonstrated duplication of internal spermatic vein draining into left renal vein; Group III: two patients had pampiniform plexus draining to iliac and/or paraspinal veins. SAS was performed in Group I and II patients. Sclerosant volume injected ranged from 1.5 to 4.5 ml. In Group III patients, surgical ligation of testicular veins was performed rather than SAS to avoid uncontrolled systemic sclerosant spillage. Mean length of stay was 1.13 day. One patient with scrotal haematoma and one other with minor wound dehiscence were managed conservatively. Mean follow-up period was 10.9 (1-22) months. Thirteen patients (86.7 %) achieved varicocele grading ≤ 1. There was no postoperative testicular atrophy, hydrocele and epididymo-orchitis. CONCLUSION: Scrotal antegrade sclerotherapy using STS foam is a safe and effective treatment for adolescent varicoceles. Anatomical variations on venous drainage in varicoceles are common.


Assuntos
Escleroterapia/métodos , Escroto/irrigação sanguínea , Varicocele/terapia , Adolescente , Adulto , Criança , Seguimentos , Humanos , Masculino , Soluções Esclerosantes/uso terapêutico , Escroto/anatomia & histologia , Tetradecilsulfato de Sódio/uso terapêutico , Testículo/anatomia & histologia , Testículo/irrigação sanguínea , Resultado do Tratamento , Adulto Jovem
10.
Stud Health Technol Inform ; 280: 109-112, 2021 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-34190070

RESUMO

Despite application of ultrasound for quantitative measurement of spinal curvatures has been reported with various studies, a systematic review for such is lacking. This systematic review aimed to evaluate (1) reliability of ultrasound; (2) validity of ultrasound using radiographic measurement as gold standard in idiopathic scoliosis patients; and (3) the use of various anatomical landmarks for measurement of spinal curvatures. MEDLINE, EMBASE, CINAHL, and CENTRAL databases were searched. QUADAS-2 quality assessment tool was adopted. Reliability of ultrasound in terms of intra-class correlation coefficient was recorded. Pearson correlation coefficients between ultrasound and radiographic measurements were extracted for meta-analysis. Subgroup analyses based on ultrasound measurement protocols of spinous process (SP), transverse processes (TP) and center of lamina (COL) were conducted. Eleven articles reporting 18 correlation analyses on 766 subjects were eligible for meta-analysis. The mean inter-rater reliability of ultrasound measurement was 0.87±0.07. Pooled correlation for all studies was 0.918 (95% CI: 0.868-0.949), exhibiting substantial heterogeneity (I2=90.50%, p<0.001). Subgroup analyses showed that pooled correlations were 0.887 for COL method (comprising 356 subjects); 0.924 for SP method (255 subjects); and 0.941 for TP method (117 subjects); all with notable heterogeneity (I2>90%, p<0.001). The overall risk of bias was rated moderate; yet publication bias was noted. Evidences showed that ultrasound was a promising non-invasive method with satisfactory validity and reliability for measuring coronal curvatures utilizing the SP, TP or COL methods. Further development of three-dimensional ultrasound towards scoliosis assessment will facilitate its translational application for managing scoliosis.


Assuntos
Escoliose , Curvaturas da Coluna Vertebral , Humanos , MEDLINE , Reprodutibilidade dos Testes , Escoliose/diagnóstico por imagem , Ultrassonografia
11.
Mar Pollut Bull ; 163: 111958, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33444997

RESUMO

Exotic species especially Asteraceae plants severely invade wetlands in Shenzhen Bay, an important part of the coast wetland in Guangdong-Hong Kong-Macau Bay Area, China. However, the reasons causing their expansion are unclear. The leaf traits and expansion indices of six invasive Asteraceae plants from the Overseas Chinese Town (OCT) wetland were studied and the results showed that nearly 45% of the total plant species (31 out of 69 species) in the OCT wetland, belonging to 15 families and 27 genera, were exotic invasive species. The expansion indices of six Asteraceae species negatively correlated with their leaf construction cost based on mass (CCM), caloric values and carbon concentration, but their relations with ash content were positive. Multiple linear regression analysis revealed that CCM was the most important factor affecting the expansion of an exotic species, indicating CCM may be an important reason causing the expansion of exotic species in coastal wetlands.


Assuntos
Asteraceae , Áreas Alagadas , China , Hong Kong , Humanos , Macau , Folhas de Planta
12.
Biomed Phys Eng Express ; 7(6)2021 09 02.
Artigo em Inglês | MEDLINE | ID: mdl-34416743

RESUMO

Synchrony Respiratory Tracking system adapted from CyberKnife has been introduced in Radixact to compensate the tumor motion caused by respiration. This study aims to compare the modeling accuracy of the Synchrony system between Radixact and CyberKnife. Two Synchrony plans based on fiducial phantoms were created for CyberKnife and Radixact, respectively. Different respiratory motion traces were used to drive a motion platform to move along the superoinferior and left-right direction. The cycle time and the amplitude of target/surrogate motion of one selected motion trace were scaled to investigate the dependence of modeling accuracy on the motion characteristic. The predicted target position, the correlation error, potential difference (Radixact only) and standard error (CyberKnife only) were extracted from raw data or log files of the two systems. The modeling accuracy was evaluated by calculating the root-mean-square (RMS) error between the predicted target positions and the input motion trace. A threshold T95 within which 95% of the potential difference or the standard error lay was defined and evaluated. Except for the motion trace with a small amplitude and a good (linear) correlation between target and surrogate motion, Radixact showed smaller RMS errors than CyberKnife. The RMS error of both systems increased with the motion amplitude and showed a decreasing trend with the increasing cycle time. No correlation was found between the RMS error and the amplitude of surrogate motion. T95 could be a good estimator of modeling accuracy for CyberKnife rather than Radixact. The correlation error defined in Radixact were largely affected by the number of fiducial markers and the setup error. In general, the modeling accuracy of the Radixact Synchrony system is better than that of the CyberKnife Synchrony system under unfavorable conditions.


Assuntos
Radiocirurgia , Marcadores Fiduciais , Movimento (Física) , Imagens de Fantasmas , Respiração
13.
Stud Health Technol Inform ; 280: 106-108, 2021 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-34190069

RESUMO

Scoliosis screening is important for timely initiation of brace treatment to mitigate curve progression in skeletally immature children. Scoliosis screening programs frequently include the protocol of referring children screened positive with Scoliometer and Moiré Topography for confirmatory standard radiography. Despite being highly sensitive (88%) for detecting those who require specialist referral, the screening program was found to have more than 50% false positive rate that leads to unnecessary radiation exposure. Radiation-free ultrasound has been reported to be reliable for quantitative assessment of scoliosis curves. The aim of this prospective diagnostic accuracy study was to determine the accuracy of ultrasound in determining the referral status for children initially screened positive for scoliosis. 442 schoolchildren with a mean Cobb angle of 14.0 ± 6.6° were recruited. Using x-ray as the gold standard, the sensitivity and specificity of ultrasound in predicting the correct referral status were 92.3% and 51.6% respectively. ROC curve analysis revealed an area under curve of 0.735 for ultrasound alone and 0.832 for ultrasound plus scoliometer measurement. The finding provided strong evidences on the accuracy of ultrasound in determining the referral status that could result in more than 50% reduction of unnecessary radiation exposure for children undergoing scoliosis screening.


Assuntos
Escoliose , Criança , Humanos , Programas de Rastreamento , Estudos Prospectivos , Radiografia , Escoliose/diagnóstico por imagem , Ultrassonografia
14.
Biomed Phys Eng Express ; 7(3)2021 04 30.
Artigo em Inglês | MEDLINE | ID: mdl-33882471

RESUMO

Purpose. This study aims to evaluate the performance of a commercial 1.5 T MR-Linac by analyzing its patient-specific quality assurance (QA) data collected during one full year of clinical operation.Methods and Materials. The patient-specific QA system consisted of offline delivery QA (DQA) and online calculation-based QA. Offline DQA was based on ArcCHECK-MR combined with an ionization chamber. Online QA was performed using RadCalc that calculated and compared the point dose calculation with the treatment planning system (TPS). A total of 24 patients with 189 treatment fractions were enrolled in this study. Gamma analysis was performed and the threshold that encompassed 95% of QA results (T95) was reported. The plan complexity metric was calculated for each plan and compared with the dose measurements to determine whether any correlation existed.Results. All point dose measurements were within 5% deviation. The mean gamma passing rates of the group data were found to be 96.8 ± 4.0% and 99.6 ± 0.7% with criteria of 2%/2mm and 3%/3mm, respectively. T95 of 87.4% and 98.2% was reported for the overall group with the two passing criteria, respectively. No statistically significant difference was found between adaptive treatments with adapt-to-position (ATP) and adapt-to-shape (ATS), whilst the category of pelvis data showed a better passing rate than other sites. Online QA gave a mean deviation of 0.2 ± 2.2%. The plan complexity metric was positively correlated with the mean dose difference whilst the complexity of the ATS cohort had larger variations than the ATP cohort.Conclusions. A patient-specific QA system based on ArcCHECK-MR, solid phantom and ionization chamber has been well established and implemented for validation of treatment delivery of a 1.5 T MR-Linac. Our QA data obtained over one year confirms that good agreement between TPS calculation and treatment delivery was achieved.


Assuntos
Planejamento da Radioterapia Assistida por Computador , Trifosfato de Adenosina , Humanos , Aceleradores de Partículas , Dosagem Radioterapêutica , Radioterapia de Intensidade Modulada
15.
Mar Pollut Bull ; 152: 110897, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31957670

RESUMO

Laguncularia racemosa and Sonneratia apetala are fast-growing exotic mangrove species in Southern China and widely used for afforestation. However, the invasiveness of the two exotic species is still unclear. We compared structural and physiological traits and energy-use related traits between L. racemosa and S. apetala, and with two natives (Kandelia obovata and Aegiceras corniculatum) in northern Fujian. Results showed that leaf construction cost based on mass (CCM) and caloric values of L. racemosa were significantly lower than S. apetala, and the two natives had highest CCM. Because lower CCM, L. racemosa grew faster with a taller height (4.83 m) and wider ground diameter circumference (40.03 cm) than S. apetala (4.43 m tall and 35.63 cm wide) and the two natives (2.42 m tall and 26.78 cm wide). These findings indicated that L. racemosa could be more invasive than S. apetala in mangrove forests in northern Fujian, China where it still grew well, which deserves more attention.


Assuntos
Combretaceae , Rhizophoraceae , China , Florestas , Folhas de Planta
16.
Clin Exp Allergy ; 39(6): 890-6, 2009 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-19226279

RESUMO

BACKGROUND: Caucasian families with food-allergic children have a compromised quality of life (QoL) for fear of life-threatening food reactions. Such data are limited in Asian children. Based on our recent questionnaire-based survey, 8.1% of young children recruited from local nurseries and kindergartens had parent-reported adverse food reactions (AFRs). OBJECTIVE: This study tested the robustness of the Chinese Food Allergy Quality of Life-Parental Burden questionnaire (FAQL-PB) and assessed QoL in families with childhood AFR. The correlations among FAQL-PB items were evaluated by factor analysis. METHODS: Two hundred and ninety-eight of 3677 children aged 2-7 years had parent-reported AFR, and 197 (66.1%) of them completed the 17 items of our self-administered FAQL-PB. Six hundred and thirty-nine (18.9%) children without AFR returned this questionnaire. Factor analysis was used to delineate the inter-relationship among the FAQL-PB items. RESULTS: Cronbach alpha for our Chinese FAQL-PB was 0.976, and the median (interquartile range) FAQL-PB scores of children with and without parent-reported AFR were 0.10 (0.02-0.32) and 0 (0-0.18), respectively (P < 0.001). Factor analysis confirmed excellent correlations between FAQL-PB items. The 17 items were clustered into two factors, which explained 79.7% of the total variance. Among children with AFR, FAQL-PB scores increased with increasing numbers of foods that caused AFRs (P < 0.001 for trend). Thirty (15.2%) children had impaired QoL, defined as average item FAQL-PB score > or = 0.5. Impaired QoL was associated with AFR that was caused by >3 foods (P = 0.001), current food avoidance (P = 0.005) and AFR caused by peanut (P = 0.003), egg (P = 0.011) and cow's milk (P = 0.028), and current flexural dermatitis (P = 0.011). CONCLUSIONS: FAQL-PB is a robust measure of AFR-specific parental QoL, which is impaired in Chinese children with parent-reported AFR. Flexural dermatitis, current food avoidance and AFR caused by multiple foods are independent risk factors for lower parental QoL.


Assuntos
Hipersensibilidade Alimentar/imunologia , Hipersensibilidade Alimentar/psicologia , Qualidade de Vida , Inquéritos e Questionários , Criança , Pré-Escolar , China , Feminino , Humanos , Masculino
17.
Science ; 195(4279): 679-81, 1977 Feb 18.
Artigo em Inglês | MEDLINE | ID: mdl-17816418

RESUMO

beta-Glucan synthesis from uridine diphosphoglucose by pea epicotyl tissue slices is increased two- to threefold by preliminary, short-term treatment with cellulases purified from auxin-treated peas. We suggest that cellulases introduce chain ends in accessible regions of cellulose microfibrils which then act as primers for chain elongation.

18.
Zhonghua Liu Xing Bing Xue Za Zhi ; 40(10): 1222-1226, 2019 Oct 10.
Artigo em Zh | MEDLINE | ID: mdl-31658521

RESUMO

Objective: To evaluate the effectiveness of the "Internet Plus-based AIDS Comprehensive Prevention Service System" among men who have sex with men in Guangzhou. Methods: Data through case-reporting and follow-up programs on MSM HIV/AIDS in Guangzhou was collected from the China Information System for Disease Control and Prevention, which including those from the referral and follow-up treatment compliance programs in 2008-2014 (pre-treatment) and 2017-2018 (post-treatment). According to the types of care services, three groups were set as: with "Internet Plus" service, with 'HIV counseling/testing service' or with 'routine medical service'. General Estimating Equation (GEE) was used to analyze the follow up situation of HIV/AIDS cases, annually. Cox proportional hazard regression model was used to analyze the proportions of treatment referral, within the 30 days of diagnosis. Results: Before the implementation of immediate treatment after HIV diagnosis, 90.6% (707/780) of the HIV/AIDS cases received the first follow up program including the CD(4)(+) T cells counts (CD(4)) test service within 90 days of diagnosis, in the "Internet Plus-based HIV/AIDS care service" group presented 1.19 times (95%CI: 1.14-1.25) of the routine medical service group. The implementation of immediate treatment after HIV diagnosis, compared with the routine medical service group, the "Internet Plus" service group presented 1.71 times (95%CI: 1.03- 2.83) more treatment referrals within the 30 days of diagnosis, when the first testing CD(4) was ≤200 cells/µl. Compared with the routine medical service group, the HIV counseling and testing service group showed 1.37 times (95%CI: 1.20-1.56) more of the treatment referrals within the 30 days of HIV diagnosis, after the first testing CD(4) counts as >200 cells/µl. Conclusion: Standardized care and follow-up service should be promoted as soon as the referral and treatment programs were set after the diagnosis was made, under the "Internet Plus-based AIDS Comprehensive Prevention Service System" for the MSM population, in Guangzhou.


Assuntos
Síndrome da Imunodeficiência Adquirida/diagnóstico , Infecções por HIV/diagnóstico , Serviços Preventivos de Saúde , Minorias Sexuais e de Gênero , Síndrome da Imunodeficiência Adquirida/prevenção & controle , China , Infecções por HIV/prevenção & controle , Homossexualidade Masculina , Humanos , Internet , Masculino
19.
Mar Pollut Bull ; 57(6-12): 716-26, 2008.
Artigo em Inglês | MEDLINE | ID: mdl-18374368

RESUMO

The remediation of mangrove sediment contaminated with mixed polycyclic aromatic hydrocarbons (PAHs) having 3-, 4- and 5-rings by natural attenuation, bioaugmentation, phytoremediation and its combination was compared by greenhouse microcosm studies. At Days 90 and 154, the decreases of PAHs in contaminated mangrove sediment by phytoremediation, planted with one-year old Aegiceras corniculatum, and bioaugmentation, the inoculation of PAH-degrading bacterial strains isolated from mangrove sediment, either SCSH (Mycobacterium parafortuitum) or SAFY (Sphingobium yanoikuyae), were not better than that by natural attenuation (the non-vegetated and un-inoculated microcosms). The populations of SCSH and SAFY in sediment could not be maintained even with repeated inoculation, suggesting that the two isolates were not able to compete with the indigenous microbes and had little enhancement effect. Although some PAHs were accumulated in roots, root uptake only accounted for <15% of the spiked PAHs and the effect of plants on remediation were also insignificant. At the end of the 154-day experiment, the mass balance calculation revealed that the overall losses of PAHs by phytoremediation were comparable to that by bioaugmentation but were lower than that by natural attenuation, especially for the high molecular weight PAHs. Under natural attenuation, around 90% fluorene, 80% phenanthrene, 70% fluoranthene, 68% pyrene and 32% benzo[a]pyrene in contaminated sediment were removed. These results demonstrated that the mangrove sediment itself had sufficient indigenous microorganisms capable of naturally remedying PAH contamination.


Assuntos
Sedimentos Geológicos/análise , Sedimentos Geológicos/microbiologia , Mycobacterium/metabolismo , Hidrocarbonetos Policíclicos Aromáticos/metabolismo , Primulaceae/metabolismo , Sphingomonadaceae/metabolismo , Poluentes Químicos da Água/metabolismo , Biodegradação Ambiental , Biomassa , Mycobacterium/fisiologia , Folhas de Planta/fisiologia , Raízes de Plantas/química , Raízes de Plantas/fisiologia , Caules de Planta/fisiologia , Hidrocarbonetos Policíclicos Aromáticos/análise , Hidrocarbonetos Policíclicos Aromáticos/química , Densidade Demográfica , Primulaceae/crescimento & desenvolvimento , Sphingomonadaceae/fisiologia , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/química
20.
Mar Pollut Bull ; 57(6-12): 695-702, 2008.
Artigo em Inglês | MEDLINE | ID: mdl-18433800

RESUMO

Biodegradation of polycyclic aromatic hydrocarbons (PAHs) in contaminated sediment is an attractive remediation technique and its success depends on biodegradation kinetics, and the optimal condition for the PAH-degrading isolates; however, information on this aspect is still scarce. The effects of multi-factors on biodegradation of phenanthrene, a 3-ring model PAH, in contaminated sediment slurry by Sphingomonas sp. a bacterial strain isolated from surface mangrove sediment, were investigated using the orthogonal experimental design (form L(16)(4(5))). The most significant factors were salinity and inoculum size, while the effects of phenanthrene concentrations, nutrient addition and temperatures were insignificant. The optimal biodegradation condition in contaminated mangrove sediment slurry was 30 degrees C, 15 ppt salinity, a carbon/nitrogen ratio of 100:1 (the background ratio in sediment) and an inoculum size of 10(6) most probable number g(-1) sediment. The phenanthrene biodegradation could be best described by the first order rate model, C=C(0)e(-kt), where k (the rate constant) is equaled to 0.1185, under the optimal condition. The kinetic model was verified and its validity in predicting biodegradation by Sphingomonas sp. at various phenanthrene concentrations was proved by experimental data.


Assuntos
Sedimentos Geológicos/microbiologia , Magnoliopsida , Hidrocarbonetos Policíclicos Aromáticos/metabolismo , Sphingomonas/metabolismo , Poluentes Químicos da Água/metabolismo , Biodegradação Ambiental , Sedimentos Geológicos/química , Cinética , Magnoliopsida/microbiologia , Fenantrenos/análise , Fenantrenos/metabolismo , Sphingomonas/isolamento & purificação
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