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1.
J Soils Sediments ; 23(2): 936-946, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36193337

RESUMO

Purpose: In recent years, microplastic (MP) contamination has raised enormous concern. However, data on the influence of solid waste treatment systems on MP pollution around agricultural soil are lacking. This study investigated the distribution and characteristics of MPs in agricultural soil surrounding a solid waste treatment center in southeastern China. Materials and methods: Fifty-seven agricultural topsoil samples around the solid waste treatment center were collected. The samples were pretreated by drying, flotation separation using NaCl solution, and digestion by H2O2. The abundance and morphological characteristics of MPs were determined by a microscope, followed by Raman spectroscopy analysis identified polymer types and SEM-EDS analysis observed surface morphology and the type of metals accumulated on the MPs. Results and discussion: Soil MPs' abundance ranged from 280 to 2360 items/kg, while a higher abundance of MPs was distributed in the downwind area. The < 1-mm MPs were dominant, and white fragment MPs were widely found. Polyethylene (52.86%) and polypropylene (27.14%) were the most common. Moreover, SEM-EDS images illustrated that MPs were significantly weathered and showed the uneven distribution of metal(loid) elements on the surface, implying that MPs may migrate as heavy metal vectors to threaten agroecosystem safety. Conclusions: This study reveals the distribution and characteristics of MPs in agricultural soil surrounding a solid waste treatment center in southeastern China, as well as the potential source of soil MPs, and provides systematic data for further research on MP pollution in agricultural soil. Supplementary Information: The online version contains supplementary material available at 10.1007/s11368-022-03341-6.

2.
Eur J Nucl Med Mol Imaging ; 49(8): 2605-2617, 2022 07.
Artigo em Inglês | MEDLINE | ID: mdl-34939176

RESUMO

PURPOSE: To surmount the critical issues of indocyanine green (ICG), and thus achieving a precise surgical navigation of primary liver cancer after long-term transcatheter arterial embolization. METHODS: In this study, a facile and green pure-nanomedicine formulation technology is developed to construct carrier-free indocyanine green nanoparticles (nanoICG), and which subsequently dispersed into lipiodol via a super-stable homogeneous lipiodol formulation technology (SHIFT nanoICG) for transcatheter arterial embolization combined near-infrared fluorescence-guided precise hepatectomy. RESULTS: SHIFT nanoICG integrates excellent anti-photobleaching capacity, great optical imaging property, and specific tumoral deposition to recognize tumor regions, featuring entire-process enduring fluorescent-guided precise hepatectomy, especially in resection of the indiscoverable satellite lesions (0.6 mm × 0.4 mm) in rabbit bearing VX2 orthotopic hepatocellular carcinoma models. CONCLUSION: Such a simple and effective strategy provides a promising avenue to address the clinical issue of clinical hepatectomy and has excellent potential for a translational pipeline.


Assuntos
Carcinoma Hepatocelular , Embolização Terapêutica , Neoplasias Hepáticas , Nanopartículas , Cirurgia Assistida por Computador , Animais , Carcinoma Hepatocelular/diagnóstico por imagem , Carcinoma Hepatocelular/cirurgia , Óleo Etiodado , Humanos , Verde de Indocianina , Neoplasias Hepáticas/diagnóstico por imagem , Neoplasias Hepáticas/cirurgia , Imagem Óptica/métodos , Coelhos , Cirurgia Assistida por Computador/métodos
3.
J Environ Manage ; 315: 115142, 2022 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-35500484

RESUMO

Oyster shell (OS) is a kind of reusable resource that can serve as carbon source, biofilms carrier and basifying agent, suggesting it is an attractive filler option for biofiltration, but studies on its application in drinking water treatment are limited. In this study, one pilot-scale up-flow filter filled with OS media were designed to pretreat surface source water. Filter performance and biological functions were investigated to determine its application scope. The results showed that effluent pH increased and was stable around 7.5 due to the alkalinity provided by OS and its buffering capacity. High and stable removal efficiencies of turbidity (mostly >60%) were achieved. The removal efficiencies of NH4+-N changed in a wide range (mostly <30%). TOC and UV254 removal rate was low (<10%). The biofilms formation period took about 45 days. During this period, this filter mainly removed pollutants through adsorption by OS. High-throughput sequencing results showed that functional taxa did not play a key role after adsorption saturation in early operation period. Functional microbial taxa formed on the OS surface after long-term operation and NH4+-N removal rate increased to some extent. Our results suggested that unburned OS filter can be used as rough filter for turbidity removal instead of coagulation and sedimentation process. Preoxidation, calcination of OS, mixed with other filler and are recommended to improve the performance if it would be used for biofiltration. This study provides an insight for the reuse of OS in drinking water treatment.


Assuntos
Água Potável , Ostreidae , Poluentes Químicos da Água , Purificação da Água , Animais , Estudos de Viabilidade , Filtração , Águas Residuárias , Poluentes Químicos da Água/análise , Purificação da Água/métodos
4.
Environ Manage ; 70(4): 650-665, 2022 10.
Artigo em Inglês | MEDLINE | ID: mdl-35907030

RESUMO

Hazardous waste pollutes the air, soil, and water and adversely affects human health if not disposed of safely. Analysis of the efficiency of hazardous waste disposal is essential to sustainable development. This paper uses the three-stage super-efficiency Data Envelopment Analysis model to measure the efficiency of 28 EU countries from 2004 to 2016. To ensure the reliability of the results, the article utilizes a one-way ANOVA statistical test to verify whether DEA results vary significantly across various EU countries. This article discusses "how inputs and outputs can be adjusted to eliminate inefficiencies" to suggest a targeted improvement. The third stage supper efficiency DEA results shows that the efficiency varies significantly across different EU countries. The main reasons for the low efficiency are high generated hazardous waste, management expenditure, greenhouse gas emissions, and inadequate waste disposal volume. Targeted proposals from three aspects are given for policymakers in EU countries: Build a resource recycling system to reduce hazardous waste. Establish a sound fee management system to reduce expenses. Optimization of disposal technology to improve incineration efficiency.


Assuntos
Eliminação de Resíduos , Gerenciamento de Resíduos , Resíduos Perigosos , Humanos , Incineração/métodos , Reciclagem , Eliminação de Resíduos/métodos , Reprodutibilidade dos Testes , Solo , Gerenciamento de Resíduos/métodos
5.
J Clin Lab Anal ; 35(7): e23858, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34165827

RESUMO

BACKGROUND: Circular RNA (circRNA) has been shown to affect the pathological process of osteoarthritis (OA) and is expected to become a potential marker for disease diagnosis. This study aimed to investigate the association between circRNA derived from the gene of runt-related transcription factor 2 (RUNX2) and OA risk. METHODS: The expression profile of RUNX2-derived circRNAs in serum of OA patients was detected. Then, the cytological localization of screened differential circRNAs was studied. Luciferase (LUC) reporter assay was used to identify the microRNA (miRNA) sponge capacity of the circRNAs. Bioinformatics analysis was used to construct the functional pathway of this circRNA-miRNAs network. And then, the diagnostic value of RUNX2-derived circRNAs in OA was evaluated. RESULTS: RUNX2-derived hsa_circ_0005526 (circ_RUNX2) is significantly highly expressed in OA serum and mainly located in the cytoplasm within the cartilage cell by sponging multiple miRNAs (miR-498, miR-924, miR-361-3p, and miR-665). Bioinformatics analysis showed ECM-receptor interaction pathway ranked the most significant pathway of circ_RUNX2-miRNAs regulatory network in KEGG database. The ROC curve showed that there may be good diagnostic value of serum circ_RUNX2 in OA. CONCLUSION: RUNX2-derived circ_RUNX2 may be involved in OA development via ECM-receptor interaction pathways and may be used as potential clinical indicator of OA.


Assuntos
Subunidade alfa 1 de Fator de Ligação ao Core/sangue , Osteoartrite/sangue , Osteoartrite/genética , RNA Circular/sangue , Matriz Extracelular/metabolismo , Regulação da Expressão Gênica , Redes Reguladoras de Genes , Humanos , MicroRNAs/genética , MicroRNAs/metabolismo , Curva ROC , Receptores de Superfície Celular/metabolismo , Frações Subcelulares/metabolismo
6.
J Environ Manage ; 298: 113458, 2021 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-34358938

RESUMO

Pseudomonas putida is potentially used in the bioremediation of heavy metals (HMs). Its response to different HMs in different environments is still not fully understood. This study investigated resistance against 12 kinds of metals by P. putida CZ1 planktonic cells and its biofilm in LB and mineral medium (MM). P. putida CZ1 biofilms have high resistance and accumulation capacity for Cu2+, Zn2+, Pb2+, Fe3+, Mn2+, Al3+ and Ni2+, but less resistance to Co2+, Cd2+, Cr2O72-, Ag+ and Hg2+. Biofilms were 2-8 times more resistant to Cu2+ and Zn2+ than planktonic cells. There was a strong correlation between the P content and the accumulation of Cu2+, Zn2+, Fe3+, Mn2+, Pb2+, Ni2+and Al3+ respectively. Confocal laser scanning microscopy (CLSM) combined with live/dead staining study found that cells in the biofilms can keep viable after 36 h under MIC of Cu2+ or Zn2+ both in LB and MM. When the metal concentration increased, cells can be killed gradually. For Cu2+, Zn2+, Fe3+, Mn2+, Pb2+ and Ni2+, higher resistance was found in MM (2-4 times higher) than in LB and higher accumulation of these metals were also found in MM. P. putida CZ1 biofilm cultured in MM with citric acid as carbon source had stronger resistance and accumulation ability to Cu2+, Zn2+, Pb2+, Fe3+, Mn2+, and Ni2+. This suggested that P. putida CZ1 had greater remediation potential for these metals in organic acid rich environments.


Assuntos
Metais Pesados , Pseudomonas putida , Biodegradação Ambiental , Biofilmes , Monitoramento Ambiental , Metais Pesados/análise , Minerais , Pseudomonas putida/genética
7.
J Environ Manage ; 265: 110350, 2020 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-32421549

RESUMO

The existence of leachable Cr(Ⅵ) in chromite ore processing residue (COPR) makes it hazardous waste. Therefore, resourceful utilization of COPR is necessary to protect the ecosystem and living biota from hazardous effect of Cr(Ⅵ) caused by its leaching. In this study, detoxification and immobilization of COPR was carried out through introduction of ascorbic acid (AA) in alkali-activated cementitious materials. Several dosages of AA were treated with water extractable/soluble Cr(Ⅵ) to achieve the optimum dosage which could be further utilized in solidification process. While, the compressive strength was developed through utilizing different modulus of water glass, liquid to solid ratios and curing temperatures. The results showed that 0.3% of AA was enough to reduce the Cr(Ⅵ) into Cr(Ⅲ), and highest compressive strength of 120 MPa was achieved after using the modulus of 1.6, liquid to solid ratio of 0.24 and curing temperature of 30 °C. The solidified samples having AA had not exceeded the toxicity limit up to 60% addition of COPR, and samples without addition of AA were effective for solidification of 20% COPR. Regarding mechanism, the compressive strength, leaching behavior and microscopic analysis i.e. X-ray diffraction (XRD), Fourier transform infrared spectrometry (FTIR) and scanning electron microscope with energy dispersive spectrometry (SEM-EDS) showed that immobilization of chromium was carried out through physical and chemical means.


Assuntos
Álcalis , Resíduos Industriais , Ácido Ascórbico , Cromo , Ecossistema
8.
Angew Chem Int Ed Engl ; 58(1): 269-272, 2019 01 02.
Artigo em Inglês | MEDLINE | ID: mdl-30421488

RESUMO

We report the rational design of coordination-driven self-assembly metal-organic nanostructures for multifunctional nanotheranostics. Zinc(II) coordination-based nano-formulations capable of loading indocyanine green (ICG) and therapeutic genes were prepared to achieve a fluorescence/photoacoustic imaging-guided combination photo/gene therapy strategy. We showed the enhanced theranostic capability of zinc(II)-dipicolylamine-assisted assembly of ICG, as well as simultaneous targeted gene delivery in an experimental mouse model of cancer. Such a co-assembly strategy provides a facile way to achieve combined therapeutic functions for personalized nanomedicine.


Assuntos
Terapia Genética/métodos , Nanomedicina/métodos , Fototerapia/métodos , Zinco/química , Humanos
10.
J Water Health ; 15(2): 218-227, 2017 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-28362303

RESUMO

Human health and biological safety problems resulting from urban drinking water pipe network biofilms pollution have attracted wide concern. Despite the inclusion of residual chlorine in drinking water distribution systems supplies, the bacterium is a recalcitrant human pathogen capable of forming biofilms on pipe walls and causing health risks. Typical drinking water bacterial biofilms and their response to different concentrations of chlorination was monitored. The results showed that the four bacteria all formed single biofilms susceptible to sodium hypochlorite. After 30 min disinfection, biomass and cultivability decreased with increasing concentration of disinfectant but then increased in high disinfectant doses. PMA-qPCR results indicated that it resulted in little cellular damage. Flow cytometry analysis showed that with increasing doses of disinfectant, the numbers of clusters increased and the sizes of clusters decreased. Under high disinfectant treatment, EPS was depleted by disinfectant and about 0.5-1 mg/L of residual chlorine seemed to be appropriate for drinking water treatment. This research provides an insight into the EPS protection to biofilms. Resistance of biofilms against high levels of chlorine has implications for the delivery of drinking water.


Assuntos
Fenômenos Fisiológicos Bacterianos , Biofilmes/efeitos dos fármacos , Desinfetantes/farmacologia , Água Potável/microbiologia , Hipoclorito de Sódio/farmacologia , Bactérias/efeitos dos fármacos , Desinfecção , Flavobacterium/fisiologia , Klebsiella/fisiologia , Pseudomonas/fisiologia , Sphingomonas/fisiologia , Purificação da Água , Abastecimento de Água
11.
Environ Sci Technol ; 49(3): 1721-8, 2015 Feb 03.
Artigo em Inglês | MEDLINE | ID: mdl-25584685

RESUMO

The occurrence of a viable but nonculturable (VBNC) state in bacteria may dramatically underestimate the health risks associated with drinking water. Therefore, the potential for UV treatment to induce a VBNC state in Escherichia coli and Pseudomonas aeruginosa was investigated. UV disinfection effectively reduced the culturability of E. coli and P. aeruginosa, with the destruction of nucleic acids demonstrated using gadA long gene fragment qPCR amplification. Following UV radiation, copy numbers for the high transcriptional levels of the 16S rRNA gene varied insignificantly in both strains, confirming results from plate counting assays indicating that VBNC states were induced in both strains. Furthermore, the virulence genes gadA and oprL remained highly expressed, suggesting that the VBNC bacteria still displayed pathogenicity. Propidium monoazide qPCR indicated that cell membranes remained intact even at a UV dose of 300 mJ/cm(2). The RT-qPCR results after UV and chlorine treatments in E. coli were significantly different (8.41 and 5.59 log units, respectively), further confirming the induction of VBNC bacteria induced by UV radiation. Finally, resuscitation was achieved, with E. coli showing greater resuscitation ability than P. aeruginosa. These results systematically revealed the potential health risks of UV disinfection and strongly suggest a combined disinfection strategy.


Assuntos
Desinfecção/métodos , Escherichia coli/efeitos da radiação , Pseudomonas aeruginosa/efeitos da radiação , Azidas , Cloro/farmacologia , Escherichia coli/efeitos dos fármacos , Escherichia coli/genética , Escherichia coli/patogenicidade , Proteínas de Escherichia coli/genética , Glutamato Descarboxilase/genética , Proteínas de Membrana/genética , Reação em Cadeia da Polimerase/métodos , Propídio/análogos & derivados , Pseudomonas aeruginosa/efeitos dos fármacos , Pseudomonas aeruginosa/genética , Pseudomonas aeruginosa/patogenicidade , RNA Ribossômico 16S/metabolismo , Raios Ultravioleta
12.
Appl Microbiol Biotechnol ; 98(3): 1309-20, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-23715854

RESUMO

Membrane biofouling, resulting from biofilm formation on the membrane, has become the main obstacle hindering wider application of membrane technology. Initial biofouling proves to be crucial which involves early stages of microbial adhesion and biofilm formation. Biological control of microbial attachment seems to be a promising strategy due to its high efficiency and eco-friendliness. The present study investigated the effects of a bacterium Bacillus pumilus SW9 on controlling the initial fouling formed by four target bacterial strains which were pioneer species responsible for biofouling in membrane bioreactors, using microfiltration membranes as the abiotic surfaces. The results suggested that strain SW9 exhibited excellent antibiofilm activity by decreasing the attached biomass of target strains. The production of extracellular polysaccharides and proteins by four target strains was also reduced. A distinct improvement of permeate flux in dead-end filtration systems was achieved when introducing strain SW9 to microfiltration experiments. Scanning electron microscopy and confocal laser scanning microscopy were performed to further ascertain significant changes of the biofouling layers. A link between biofilm inhibition and initial biofouling mitigation was thus provided, suggesting an alternatively potential way to control membrane biofouling through bacterial interactions.


Assuntos
Antibiose , Bacillus/fisiologia , Biofilmes/crescimento & desenvolvimento , Incrustação Biológica , Microbiologia Ambiental , Filtração , Purificação da Água , Aderência Bacteriana/efeitos dos fármacos , Biofilmes/efeitos dos fármacos , Membranas Artificiais , Microscopia Confocal , Microscopia Eletrônica de Varredura
13.
World J Microbiol Biotechnol ; 30(12): 3081-90, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25217027

RESUMO

The extracellular polymeric substance (EPS) and surface properties of unsaturated biofilms of a heavy metal-resistant rhizobacterium Pseudomonas putida CZ1, in response to aging, pH, temperature and osmotic stress, were studied by quantitative analysis of EPS and atomic force microscope. It was found that EPS production increased approximately linearly with culture time, cells in the air-biofilm interface enhanced EPS production and decreased cell volume to cope with nutrient depletion during aging. Low pH, high temperature and certain osmotic stress (120 mM NaCl) distinctly stimulated EPS production, and the main component enhanced was extracellular protein. In addition to the enhancement of EPS production in response to high osmotic (328 mM NaCl) stress, cells in the biofilm adhere tightly together to maintain a particular microenvironment. These results indicated the variation of EPS composition and the cooperation of cells in the biofilms is important for the survival of Pseudomonas putida CZ1 from environmental stresses in the unsaturated environments such as rhizosphere.


Assuntos
Biofilmes/crescimento & desenvolvimento , Biopolímeros/metabolismo , Pseudomonas putida/fisiologia , Estresse Fisiológico , Propriedades de Superfície , Aderência Bacteriana , Concentração de Íons de Hidrogênio , Microscopia de Força Atômica , Pressão Osmótica , Pseudomonas putida/efeitos dos fármacos , Pseudomonas putida/efeitos da radiação , Cloreto de Sódio/metabolismo , Temperatura
14.
J Environ Sci (China) ; 26(8): 1763-8, 2014 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-25108733

RESUMO

A combined approach of physicochemical extraction and sulfur K-edge X-ray absorption near-edge structure (XANES) spectroscopy was applied to characterize the extracellular polymeric substances (EPS) of typical bacterial biofilms in this study. Physicochemical analysis showed variation of the contents of DNA, polysaccharide and protein in different fractions of EPS in different mediums. The sulfur K-edge XANES analysis yielded a variety of spectra. Spectral fitting of the XANES spectra utilizing a large set of model compounds showed that there was more reduced sulfur in both LB-EPS (loosely bound EPS) and TB-EPS (tightly bound EPS) of all the biofilms in LB medium than in R2A medium. More oxidized sulfur was identified in LB-EPS than that in TB-EPS, suggesting different niches and physiological heterogeneity in the biofilms. Our results suggested that the sulfur K-edge XANES can be a useful tool to analyze the sulfur speciation in EPS of biofilms.


Assuntos
Bactérias/química , Bactérias/metabolismo , Biofilmes , Polímeros/química , Polímeros/metabolismo , Enxofre/química , Espectroscopia por Absorção de Raios X/métodos , Bactérias/classificação
15.
Nanoscale ; 16(24): 11411-11428, 2024 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-38860512

RESUMO

The repurposing of existing drugs, referred to as theranostics, has made profound impacts on precision medicine. Indocyanine green (ICG), a well-established and clinical dye, has continued to be a star agent, described as a multifunctional molecule with concurrent photo- or sono-sensitiveness capabilities and co-delivery accessibility, showing remarkable potential in the area of unimodal or multimodal imaging-guided therapy of various diseases, leading to the extensive consideration of immediate clinical translations. In this review, we strive to bring the understanding of repurposing performance assessment for ICG into practice by clarifying the relationships between its features and applicability. Specifically, we address the obstacles encountered in the process of developing an ICG repurposing strategy, as well as the noteworthy advancements made in the field of ICG repurposing. We also go into detail about the structure-function correlations of drugs containing ICG and how different structural groups significantly affect the physicochemical properties.


Assuntos
Reposicionamento de Medicamentos , Verde de Indocianina , Verde de Indocianina/química , Humanos , Animais , Nanomedicina Teranóstica , Corantes/química
16.
Infect Drug Resist ; 17: 2531-2540, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38933777

RESUMO

Purpose: Previous studies have indicated that the development of severe adverse events is associated with linezolid peak concentration (Cmax), but the factors affecting linezolid Cmax and evidences on therapeutic drug monitoring to anticipate toxicity in drug-resistant tuberculosis (DR-TB) patients have not been clarified clearly. This study aimed to explore the factors influencing linezolid Cmax and investigate the association between linezolid concentration and hematological toxicity. Patients and Methods: This study included patients with drug-resistant tuberculosis treated with linezolid from January 2022 to September 2023. We analyzed the factors affecting linezolid Cmax using chi-squared and binary logistic regression. The diagnostic utility of linezolid Cmax in predicting hematological toxicity was evaluated using receiver operating characteristic (ROC) analysis. Results: A total of 76 patients were enrolled in the study. 63.20% met the standard rates for linezolid Cmax. Age (P=0.036), weight (P=0.0016), and creatinine clearance (P=0.0223) significantly correlated with the Cmax. Hematological toxicity was observed in 46.05% (35/76) of patients, characterized by thrombocytopenia (31.58%, 24/76), anemia (6.58%, 5/76), and leukopenia (21.05%, 16/76). ROC curve analysis confirmed the predictive value of linezolid Cmax for thrombocytopenia with an area under curve of 0.728. Conclusion: Suboptimal linezolid Cmax was prevalent among patients with DR-TB, with age, weight, and renal function emerging as influential factors. Elevated linezolid Cmax increases the risk of thrombocytopenia. Meticulous monitoring of linezolid Cmax is imperative during anti-DR-TB therapy to tailor treatment and mitigate hematological toxicity.

17.
Int J Mol Sci ; 14(6): 11113-24, 2013 May 24.
Artigo em Inglês | MEDLINE | ID: mdl-23708108

RESUMO

In order to investigate the microbe-mineral interaction in the micro scale, spatial distribution and speciation of Cu and S in Halothiobacillus HT1 biofilm formed on a CuS surface was examined using synchrotron-based X-ray techniques. Confocal laser scanning microscope (CLSM) results indicated that Halothiobacillus HT1 biofilm formation gave rise to distinct chemical and redox gradients, leading to diverse niches in the biofilm. Live cells were distributed at the air-biofilm and membrane-biofilm interface. CuS was oxidized by Halothiobacillus HT1 biofilm, and copper penetrated into the biofilm. Sulfide was oxidized to cysteine (77.3%), sulfite (3.8%) and sulfonate (18.9%). Cu-cysteine-like species were involved in the copper homeostasis. These results significantly improve our understanding of the interfacial properties of the biofilm-mineral interface.


Assuntos
Biofilmes/efeitos dos fármacos , Cobre/farmacologia , Halothiobacillus/citologia , Halothiobacillus/fisiologia , Síncrotrons , Halothiobacillus/efeitos dos fármacos , Viabilidade Microbiana/efeitos dos fármacos , Microscopia de Fluorescência , Enxofre/isolamento & purificação , Espectroscopia por Absorção de Raios X , Raios X
18.
J Environ Biol ; 34(2 Spec No): 325-30, 2013 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-24620601

RESUMO

Due to its potential to form toxic nitrogenous disinfection byproducts (N-DBPs), dissolved organic nitrogen (DON) is considered as one of the most important parameters in wastewater treatment plants (WWTP). This study describes a comprehensive investigation of variations in DON levels in orbal oxidation ditches. The results showed that DON increased gradually from 0.71 to 1.14 mg I(-1) along anaerobic zone, anoxic zone, aerobic zone 1 and aerobic 2. Molecular weight fractionation of DON in one anaerobic zone and one aerobic zone (aerobic zone 2) was performed. We found that the proportion of small molecular weight (<6 kDa) decreased and large molecular weight (> 20 kDa) showed opposite trend. This variation may have been caused due to the release of different types of soluble microbial products (SMPs) during biological processes. These SMPs contained both tryptophan protein-like and aromatic protein-like substances, which were confirmed by three-dimensional excitation-emission matrix (EEM) analysis.


Assuntos
Nitrogênio/química , Eliminação de Resíduos Líquidos/métodos , Poluentes Químicos da Água/química , Purificação da Água/métodos , Nitrificação
19.
J Environ Biol ; 34(2 Spec No): 353-8, 2013 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-24620605

RESUMO

Mycotoxins are considered as the most hazardous fungal metabolites for human, animals and plant health. Recently, more attention has been paid on the occurrence of this group of fungi in different water sources throughout the globe. In this study, Aspergillus parasiticus ATCC strain was used as representative strain producing aflatoxins in drinking water. This study aimed to investigate the activation of fungi in drinking water and their ability to produce aflatoxins (B1, B2, G1, and G2) in water under different ratios of C:N using different concentrations of total organic carbon (TOC) and total nitrogen (TN). Glucose and ammonium sulphate were used for changing the levels of TOC and TN in the selected water media. Similarly, the effects of different water pH levels from 4.5 to 8.2 on the growth of this group of fungi and aflatoxins production were also investigated. The results indicate that the growth of fungi was highest, at C:N ratio of 1:1 as compared to other selected ratios. Furthermore, the findings indicate that the pH levels 5.5-6.5 showed best growth of fungi as compared to other pH levels. Aflatoxin concentrations were measured in the water samples using HPLC technique, but selected fungi were not able to produce aflatoxins in water at applied concentrations of TOC and TN mimicking the ratios and concentrations present in the natural aquatic environment.


Assuntos
Aflatoxinas/metabolismo , Aspergillus/efeitos dos fármacos , Carbono/farmacologia , Nitrogênio/farmacologia , Microbiologia da Água , Carbono/química , Água Potável/microbiologia , Concentração de Íons de Hidrogênio , Nitrogênio/química , Poluentes Químicos da Água/química , Poluentes Químicos da Água/metabolismo
20.
Environ Sci Pollut Res Int ; 30(58): 121475-121486, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37950780

RESUMO

Deliberate media selection can be conducted to achieve targeted objective in filters. In this study, three biofilters (BFs) packed with calcinated oyster shell (COS), granular activated carbon (GAC), and COS + GAC (Mix) were set up in parallel following a rough filter packed with natural oyster shell to compare the performance for treating micro-polluted source water. Different media showed selective removal effects for different pollutants. GAC outperformed COS in terms of TOC and UV254. COS achieved higher reduction in turbidity than GAC. Due to the removal of total bacteria, the absolute and relative abundance of antibiotic resistance genes (ARGs) both decreased much in rough filter treated water (1.16 × 1014 to 1.40 × 1013 copies L-1 and 81.6 to 36.9%, respectively). The highest diverse and rich bacterial community was found in the biofilms on the COS filler, so microbial leakage gave rise to high bacterial content, leading to the highest absolute abundance of ARGs in COS BF effluent (2.11 × 1013 copies L-1). The highest relative abundance of ARGs (41.2%) was found in GAC BF effluent. SourceTracker and biomarker analysis both suggested that treatment process played a more important role in shaping the bacterial community structure in Mix BF effluent than single media BFs, which contributed to the lowest absolute (8.69 × 1012 copies L-1) and relative abundance (25.2%) of ARGs in Mix BF effluent among the three BFs. Our results suggested that mix COS + GAC can not only give full play to their respective advantages for traditional pollutants, but also achieve highest reduction in ARGs.


Assuntos
Água Potável , Poluentes Ambientais , Ostreidae , Poluentes Químicos da Água , Purificação da Água , Animais , Carvão Vegetal/química , Água Potável/química , Filtração/métodos , Bactérias/genética , Purificação da Água/métodos , Antibacterianos
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