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1.
Chemosphere ; 248: 126000, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32007774

RESUMO

Recently, the technology for the remediation of Cr(VI) pollutant via bisulfite has been found to be effective for fast elimination of co-contaminants especially in acidic solution, where free radicals (i.e., sulfate and/or hydroxyl radicals) are proposed to act as dominant oxidants. Here, it was demonstrated that high-valent Cr intermediate played a primary role in the Cr(VI)/bisulfite system through applying methyl phenyl sulfoxide (PMSO) as a probe. PMSO was effectively transformed in the Cr(VI)/bisulfite system with appreciable generation of methyl phenyl sulfone (PMSO2) product, while PMSO was oxidized by free radicals to hydroxylated and/or polymeric products rather than PMSO2. The involvement of high-valent Cr species was further supported by the formation of 18O-labeled PMSO2 in 18O labeling experiments, where the incorporation of 18O from solvent water H218O into PMSO2 was likely resulted from competitive oxygen exchange of Cr-oxo species with water. The relative contribution of high valent Cr species versus free radicals was evaluated based on the yield of PMSO2, which was dependent on the solution chemistry such as [Cr(VI)]:[bisulfite] ratio and dissolved oxygen. This work advances the understanding of chromium chemistry involved in the Cr(VI)/bisulfite system. These findings have important implications on the application of this "waste control by waste" technology for environmental decontamination.


Assuntos
Cromo/química , Poluentes Ambientais/química , Sulfitos/química , Derivados de Benzeno , Radicais Livres , Radical Hidroxila , Modelos Químicos , Oxidantes , Oxirredução , Sulfatos
2.
Sci Total Environ ; 657: 819-826, 2019 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-30677947

RESUMO

Although health benefits of physical activity are well known, the risk of physical activity in polluted air is unclear. Our objective is to investigate health effects resulting from physical activity in polluted air by looking at particle deposition in human tracheobronchial (TB) airways. Airflow and particle deposition in TB airways were investigated using a computational fluid dynamics (CFD) method. We chose three regional airways: upper (G3-G5), central (G9-G11) and lower (G14-G16). Physical activity was described by breathing rate at the mouth, for three levels of activity: sedentary (15 l/min), moderate (30 l/min) and intense (60 l/min). We found that particle deposition was strongly affected by physical activity. Particles are deposited in greater number in the lower airways (G14-G16) during sedentary activity, more in the upper airways (G3-G5) during intense activity, and uniformly in the airways during moderate activity. The difference in the deposition pattern was due to the reason that physical activity increased the airflow which increased inertial impaction. Our modeling of particle deposition in the human respiratory airways shows that there are different health effects for different activity levels: sedentary activity leads to chronic health effects, intense activity results in acute effects, and moderate activity minimizes the adverse health effects of physical activity in polluted air.


Assuntos
Poluentes Atmosféricos/efeitos adversos , Exercício Físico , Modelos Biológicos , Sistema Respiratório/efeitos dos fármacos , Poluentes Atmosféricos/química , Simulação por Computador , Humanos , Hidrodinâmica , Tamanho da Partícula , Material Particulado/efeitos adversos
3.
Ecotoxicol Environ Saf ; 154: 221-227, 2018 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-29476971

RESUMO

BACKGROUND: Common cold is a frequent upper respiratory tract infection, but the role of ambient temperature in the infection is unclear. OBJECTIVE: We investigated the role of prenatal exposure to diurnal temperature variation (DTV), the difference between the daily maximal and minimal temperatures, in the risk of common cold in children. METHODS: We conducted a cohort study of 2598 preschool children in Changsha, China. Occurrence of common cold during the past year was surveyed using questionnaire. We then estimated each child's prenatal exposure to DTV during pregnancy. Multivariate logistic regression model was used to examine the association between occurrence of common cold and prenatal exposure to DTV in terms of odds ratios (OR) and 95% confidence interval (CI). RESULTS: About 45% children have common cold (≥3 times) during the past year. We found that common cold in children was associated with maternal DTV exposure during pregnancy, particularly during the first trimester with adjusted OR (95% CI) = 1.27 (1.10-1.46). Male and atopic children were more susceptible to the effect of DTV during pregnancy. The risk of common cold due to DTV is higher in children living in the suburban areas and the bigger houses and in those exposed to environmental tobacco smoke, mold/dampness, new furniture and redecoration. We observed that the risk of common cold in children has been increased in recent years due to increasing DTV. CONCLUSIONS: Common cold in children was associated with maternal exposure to temperature variation during pregnancy, suggesting that the risk of common cold may originate in pregnancy.


Assuntos
Resfriado Comum/epidemiologia , Exposição Materna , Efeitos Tardios da Exposição Pré-Natal , Temperatura , Criança , Pré-Escolar , China/epidemiologia , Estudos de Coortes , Feminino , Humanos , Modelos Logísticos , Masculino , Gravidez , Fatores de Risco , Poluição por Fumaça de Tabaco
4.
J Therm Biol ; 69: 288-293, 2017 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-29037396

RESUMO

BACKGROUND: Pneumonia has been widely recognized as the leading cause of death in children worldwide, but its etiology still remains unclear. OBJECTIVE: We examined the association between maternal exposure to ambient air temperature during pregnancy and lifetime pneumonia in the offspring. METHODS: We conducted a cohort study of 2598 preschool children aged 3-6 years in Changsha, China. The lifetime prevalence of pneumonia was assessed using questionnaire. We backwards estimated each child's exposure to air temperature during prenatal and postnatal periods. Multiple regression model was used to examine the association between childhood pneumonia and exposure to air temperature in terms of odd ratios (OR) and 95% confidence interval (CI). RESULTS: Prevalence of childhood pneumonia in Changsha was high up to 38.6%. We found that childhood pneumonia was significantly associated with prenatal exposure to air temperature, with adjusted OR (95% CI) = 1.77 (1.23-2.54) for an interquartile range (IQR) increase in temperature, particularly during the second trimester with adjusted OR (95% CI) = 2.26 (1.32-3.89). Boys are more susceptible to the risk of pneumonia due to air temperature than girls. We further observed that maternal exposure to extreme heat days during pregnancy increased the risk of pneumonia in the offspring. CONCLUSIONS: Maternal exposure to air temperature during pregnancy, particularly the second trimester, was associated with pneumonia in the children, providing the evidence for fetal origins of pneumonia.


Assuntos
Exposição Ambiental/efeitos adversos , Temperatura Alta/efeitos adversos , Exposição Materna/efeitos adversos , Pneumonia/etiologia , Efeitos Tardios da Exposição Pré-Natal/etiologia , Criança , Pré-Escolar , China/epidemiologia , Estudos Transversais , Feminino , Humanos , Masculino , Gravidez , Fatores de Risco
5.
Int J Ophthalmol ; 9(1): 132-8, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-26949623

RESUMO

AIM: To assess possible benefits of intravitreal triamcinolone acetonide (IVTA) injection as pretreatment for macular laser photocoagulation (MLP) in patients with diabetic macular edema (DME). METHODS: Published randomized controlled trials (RCTs) concerning MLP with or without IVTA pretreatment for DME were retrieved from databases CNKI, Medline, EMbase, Web of Science, and the Cochrane Library. A Meta-analysis on eligible studies was conducted using RevMan 5.0 software. Two investigators independently assessed the quality of the trials and extracted data. Main outcome measures included the change in best corrected visual acuity (BCVA), difference in central macular thickness (CMT) and adverse events reporting in particular elevated intraocular pressure within the follow-up period. The results were pooled using weight mean difference (WMD) or odds risk (OR) with their corresponding 95% confidence intervals (CI). A fixed- or random-effect model was employed depending on the heterogeneity of the inclusion trials. RESULTS: Finally, five independent RCTs were identified and used for comparing MLP with IVTA pretreatment (131 eyes) with MLP alone (133 eyes, control group). The overall study quality was relatively higher according to the modified Jadad scale. The Meta-analysis showed that MLP with IVTA pretreatment significantly reduced CMT at one, three and six months (P=0.002, 0.0003 and 0.04, respectively), compared with MLP alone. The IVTA pretreatment group showed statistically significant improvements in BCVA at the one-month follow up as compared with the control group (P=0.03). At three- and six-month follow up, there was a beneficial trend towards improving visual acuity in the IVTA pretreatment group without statistical significance between groups (P=0.06 and 0.20, respectively). The incidence of elevation of intraocular pressure was significantly higher in the IVTA pretreatment group than in the control group (P<0.0001). No evidence of publication bias was present according to Begg's test and Egger's test. There was a low level of heterogeneity in the included studies. CONCLUSION: This Meta-analysis indicates that MLP with IVTA pretreatment has a better therapeutic effect in terms of CMT reduction and earlier (1mo) visual improvement for patients with DME as compared with MLP alone. Further confirmation with rigorously well-designed multi-center trials is needed.

6.
Neurol Sci ; 35(11): 1701-6, 2014 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-24816679

RESUMO

Neural tube defects (NTDs) are the most common and severe malformations of the central nervous system. The association of single nucleotide polymorphisms (SNPs) of the Frizzled 3 (FZD3) and Frizzled 6 (FZD6) genes and NTDs in the Han population of northern China was principally studied. One synonymous SNP (rs2241802) in FZD3 gene and three nonsynonymous SNPs (rs827528, rs3808553 and rs12549394) in FZD6 gene were analyzed by polymerase chain reaction (PCR) and sequencing methods in 135 NTD patients and 135 normal controls. The allele, genotype and haplotype frequencies were calculated and analyzed to examine the relationship between FZD3/FZD6 SNPs and NTDs. Both T allele and TT genotype frequencies of the FZD6 rs3808553 loci in the NTDs group were significantly higher than those in the controls, and children with T allele and TT genotype were associated with increased NTDs risk (OR = 1.575, 95 % CI 1.112-2.230, P = 0.010 and OR = 2.811, 95 % CI 1.325-5.967, P = 0.023, respectively). There were no differences among different genotypes or alleles in other three SNPs. Haplotypes A-G-C and A-T-C in FZD6 were found associated with NTDs in the case-control study (OR = 0.560, 95 % CI 0.378-0.830, P = 0.004 and OR = 1.670, 95 % CI 1.126-2.475, P = 0.011, respectively). The rs3808553 of FZD6 is obviously associated with NTDs in Han population of northern China. The TT genotype may increase risk for NTDs.


Assuntos
Grupo com Ancestrais do Continente Asiático/genética , Receptores Frizzled/genética , Predisposição Genética para Doença/genética , Defeitos do Tubo Neural/genética , Polimorfismo de Nucleotídeo Único , Estudos de Casos e Controles , Pré-Escolar , Feminino , Genótipo , Humanos , Masculino , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Fatores de Risco
7.
J Environ Sci (China) ; 16(5): 762-4, 2004.
Artigo em Inglês | MEDLINE | ID: mdl-15559807

RESUMO

The experiments on pollutant movement in surf zone were conducted on the two gentle beaches (with slope of 1:100 and 1:40, respectively), for diverse wave cases. The movement contours and direction of pollutants, under the action of regular and random waves with diverse wave amplitudes, were provided and studied in this paper. It was shown that, due to complicated hydrodynamics in surf zone, the pollutant movement state is quite complicated and different from that in pure current zone.


Assuntos
Praias , Modelos Teóricos , Movimentos da Água , Poluentes Químicos da Água/análise , China , Água do Mar
8.
J Environ Sci (China) ; 16(2): 293-6, 2004.
Artigo em Inglês | MEDLINE | ID: mdl-15137658

RESUMO

The planar 2D k-epsilon double equations' turbulence model was adopted and transformed into non-orthogonal curvilinear coordinates. The concentration convection-diffusion was introduced to planar 2D SIMPLEC algorithm of flow in non-orthogonal curvilinear coordinates. The numerical model of pollutant transportation in non-orthogonal curvilinear coordinates was constructed. The model was applied to simulate the flow and pollutant concentration fields. In the testing concentration field, two optimal operations of contamination discharging both along bank and in the centerline at the first bend of the meandering channel were adopted. Comparison with available data showed the model developed was successful, was valuable to engineering application.


Assuntos
Modelos Teóricos , Rios , Poluentes Químicos da Água/análise , Algoritmos , Difusão
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