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1.
Nat Commun ; 15(1): 4997, 2024 Jun 12.
Artigo em Inglês | MEDLINE | ID: mdl-38866737

RESUMO

Despite potential in high-resolution and low-cost displays and lighting, multi-doping structures and low concentrations (<1%) limit repeatability and stability of single-emissive-layer white light-emitting devices. Herein, we report a singly doped white-emitting system of blue thermally activated delayed fluorescence host matrix (CzAcSF) doped by yellow Cu4I4 cluster ([tBCzDppy]2Cu4I4). CzAcSF:x% [tBCzDppy]2Cu4I4 films realize photo- and electro-luminescence colors from cool white to warm white at x = 20-40. The external quantum efficiency of 23.5% was achieved at x = 30, indicating the record-high efficiency among solution-processed analogs and the largest doping concentration among efficient white light-emitting devices. It shows that di(tert-butyl)carbazole moieties in [tBCzDppy]2Cu4I4 provide high-lying excited energy levels at~2.6 eV to mediate energy transfer from CzAcSF (2.9 eV) to coordinated Cu4I4 (2.2 eV). Our results demonstrate the antenna effect of ligands on optimizing charge and energy transfer in organic-cluster systems and superiority of white cluster light-emitting diodes in practical applications.

2.
Environ Res ; 242: 117712, 2024 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-37993045

RESUMO

Although flavins are known as effective electron mediators, the binding capacity of exogenous flavins by anaerobic granular sludge (AGS) and their role in interspecies electron transfer (IET) remains unknown. In this study, AGS was mediated by using three exogenous flavins of riboflavin (RF), flavin mononucleotide (FMN), and flavin adenine dinucleotide (FAD). Results showed that the total amounts of flavins associated with extracellular polymeric substance (EPS) of AGS increased by 2.03-2.42 and 3.83-4.94 folds, after exposure to 50 and 200 µM of exogenous flavins, respectively. A large portion of FMN and FAD was transformed into RF by AGS. Exogenous flavin mediation also stimulated the production of EPS and cytochrome c (c-Cyts) as well as cytochrome-bound flavins. The increased abundance of these electron mediators led to a reduced electrochemical impedance of EPS and improved extracellular electron transfer capacity. The methane production of AGS after mediation with exogenous RF, FMN, and FAD increased by 19.03-31.71%, 22.86-26.04%, and 28.51-33.44%, respectively. This study sheds new light on the role of exogenous flavins in promoting the IET process of a complex microbial aggregate of AGS.


Assuntos
Dinitrocresóis , Flavina-Adenina Dinucleotídeo , Esgotos , Flavina-Adenina Dinucleotídeo/metabolismo , Mononucleotídeo de Flavina/metabolismo , Elétrons , Anaerobiose , Matriz Extracelular de Substâncias Poliméricas/metabolismo , Riboflavina/metabolismo , Suplementos Nutricionais , Metano
3.
Contrast Media Mol Imaging ; 2022: 2837905, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35360261

RESUMO

Purpose: To explore the value of intravoxel incoherent motion diffusion-weighted imaging (IVIM-DWI) and texture analysis on T2-weighted imaging (T2WI) for evaluating pathological differentiation of cervical squamous cell carcinoma. Method: This retrospective study included a total of 138 patients with pathologically confirmed poor/moderate/well-differentiated (71/49/18) who underwent conventional MRI and IVIM-DWI scans. The values of ADC, D, D ∗ , and f and 58 T2WI-based texture features (18 histogram features, 24 gray-level co-occurrence matrix features, and 16 gray-level run length matrix features) were obtained. Multiple comparison, correlation, and regression analyses were used. Results: For IVIM-DWI, the ADC, D, D ∗ , and f were significantly different among the three groups (p < 0.05). ADC, D, and D ∗ were positively correlated with pathological differentiation (r = 0.262, 0.401, 0.401; p < 0.05), while the correlation was negative for f (r = -0.221; p < 0.05). The comparison of 52 parameters of texture analysis on T2WI reached statistically significant levels (p < 0.05). Multivariate logistic regression analysis incorporated significant IVIM-DWI, and texture features on T2WI showed good diagnostic performance both in the four differentiation groups (poorly vs. moderately, area under the curve(AUC) = 0.797; moderately vs. well, AUC = 0.954; poorly vs. moderately and well, AUC = 0.795; and well vs. moderately and poorly, AUC = 0.952). The AUCs of each parameters alone were smaller than that of each regression model (0.503∼0.684, 0.547∼0.805, 0.511∼0.712, and 0.636∼0.792, respectively; pairwise comparison of ROC curves between regression model and individual variables, p < 0.05). Conclusions: IVIM-DWI biomarkers and T2WI-based texture features had potential to evaluate the pathological differentiation of cervical squamous cell carcinoma. The combination of IVIM-DWI with texture analysis improved the predictive performance.


Assuntos
Carcinoma de Células Escamosas , Neoplasias do Colo do Útero , Biomarcadores , Carcinoma de Células Escamosas/diagnóstico por imagem , Imagem de Difusão por Ressonância Magnética/métodos , Feminino , Humanos , Imageamento por Ressonância Magnética , Estudos Retrospectivos , Neoplasias do Colo do Útero/diagnóstico por imagem , Neoplasias do Colo do Útero/patologia
4.
Int J Hyperthermia ; 39(1): 475-484, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35271784

RESUMO

OBJECTIVE: This study aimed to assess the predictive value of conventional magnetic resonance imaging (MRI) combined with radiomics in determining the nonperfused volume ratio (NPVR) following high-intensity focused ultrasound (HIFU) ablation for uterine fibroids. METHODS AND MATERIALS: A total of 216 symptomatic uterine fibroids in 216 women were subjected to HIFU ablation from October 2015 to March 2020. Baseline clinical and MR parameters acquired before and after HIFU ablation were analyzed, and the NPVR was calculated accordingly. Radiomics features were extracted using A.K. software on T2-weighted imaging (T2WI). The minimum redundancy and maximum relevancy (mRMR) method were used to refine the selected radiomics features. Then, multiple linear regression models, the Wilcoxon signed-rank test, and Spearman's rank correlation and Bland-Altman analyses were conducted. RESULTS: Conventional MRI combined with radiomics revealed the signal intensity on T2WI (X9), enhancement degree on T1-weighted imaging (T1WI) (X11), uterine fibroid location (X4), wavelet_glszm_SizeZoneNonUniformity first order (X12) and wavelet_HHH_firstorder_Skewness (X13) negatively affected the NPVR. The resulting regression equation was NPVR = 104.030 - 11.886 × X9 - 5.459 × X11 - 2.776 × X4 - 0.20 × X12 - 16.913 × X13. The adjusted R2 values of the conventional MRI model and combined model were 0.385 and 0.408, respectively, and the two fitted models were statistically significant (p < 0.05). No significant differences were observed between the predicted NPVR value [81 (71, 91) %] of the combined model and the actual NPVR value [89 (77, 97) %] (p > 0.05). In addition, the predicted NPVR was correlated with the actual NPVR (r = 0.655, p < 0.001). CONCLUSIONS: The efficiency of the combined model was better than that of the conventional MRI model in predicting the NPVR following HIFU ablation for uterine fibroids. Radiomics is an important supplemental modality to conventional MRI.


Assuntos
Ablação por Ultrassom Focalizado de Alta Intensidade , Leiomioma , Neoplasias Uterinas , Feminino , Ablação por Ultrassom Focalizado de Alta Intensidade/métodos , Humanos , Leiomioma/diagnóstico por imagem , Leiomioma/cirurgia , Imageamento por Ressonância Magnética/métodos , Resultado do Tratamento , Neoplasias Uterinas/diagnóstico por imagem , Neoplasias Uterinas/cirurgia
5.
Water Res ; 216: 118293, 2022 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-35306457

RESUMO

Anaerobic granular sludge (AGS) is a promising technology for organic wastewater treatment and energy recovery. In this study, three different kinds of Fe and Fe oxides nanoparticles (Fe3O4, Fe2O3 and ZVI) were tried to be incorporated into AGS through direct loading or aided with biofilm disassembly agents of norspermidine and D-tyrosine, which was aimed to enhance methane production capacity of AGS via increasing redox activity of extracellular polymer substance (EPS) and interspecies electron transfer. Despite the loading methods, incorporation of Fe and Fe oxides nanoparticles into AGS increased methane production capacity remarkably, with an enhancement of 36.49-85.17%, 20.37-204.95% and 189.71-243.32%, respectively, for the Fe3O4, Fe2O3 and ZVI loaded AGS. Pretreatment of AGS using biofilm disassembly agents helped to incorporate more Fe and Fe oxides into the inner structure of AGS, which further enhanced methane production capacity by 48.68% and 184.58%, respectively, for the Fe3O4 and Fe2O3 loaded AGS. Loading Fe and Fe oxides into AGS not only introduced exogenous conductive substances and Fe(III)/Fe(II) redox couples into EPS matrix of AGS, but also stimulated the production of redox active components of flavins and c-Cyts. All these factors may contribute to the reduced resistance of EPS, enhanced interspecies electron transfer and methane production capacity of AGS. This study provides a novel strategy and facile method to accelerate interspecies electron transfer and enhance methane production for matured AGS.


Assuntos
Nanopartículas , Esgotos , Anaerobiose , Reatores Biológicos , Matriz Extracelular de Substâncias Poliméricas/metabolismo , Compostos Férricos , Metano/metabolismo , Oxirredução , Óxidos , Polímeros
6.
J Magn Reson Imaging ; 56(3): 658-667, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-35090079

RESUMO

BACKGROUND: Lymph node (LN) staging plays an important role in treatment decision-making. Current problem is that preoperative detection of LN involvement is always highly challenging for radiologists. PURPOSE: To explore the value of the nomogram model combining intravoxel incoherent motion diffusion-weighted imaging (IVIM-DWI) and radiomics features from the primary lesion of rectal adenocarcinoma in assessing the non-enlarged lymph node metastasis (N-LNM) preoperatively. STUDY TYPE: Retrospective. POPULATION: A total of 126 patients (43% female) comprising a training group (n = 87) and a validation group (n = 39) with pathologically confirmed rectal adenocarcinoma. FIELD STRENGTH/SEQUENCE: A 3.0 Tesla (T); T2 -weighted imaging (T2 WI) with fast spin-echo (FSE) sequence; IVIM-DWI spin-echo echo-planar imaging sequence. ASSESSMENT: Based on pathological analysis of the surgical specimen, patients were classified into negative LN (LN-) and positive LN (LN+) groups. Apparent diffusion coefficient (ADC), diffusion coefficient (D), pseudo diffusion coefficient (D*) and microvascular volume fraction (f) values of primary lesion of rectal adenocarcinoma were measured. Three-dimensional (3D) radiomics features were measured on T2 WI and IVIM-DWI. A nomogram model including IVIM-DWI and radiomics features was developed. STATISTICAL TESTS: General_univariate_analysis and multivariate logistic regression were used for radiomics features selection. The performance of the nomogram was assessed by the receiver operating characteristic (ROC) curve, calibration, and decision curve analysis (DCA). RESULTS: The LN+ group had a significantly lower D* value ([13.20 ± 13.66 vs. 23.25 ± 18.71] × 10-3  mm2 /sec) and a higher f value (0.43 ± 0.12 vs. 0.34 ± 0.10) than the LN- group in the training cohort. The nomogram model combined D*, f, and radiomics features had a better evaluated performance (AUC = 0.864) than any other model in the training cohort. DATE CONCLUSION: The nomogram model including IVIM-DWI and MRI radiomics features in the primary lesion of rectal adenocarcinoma was associated with the N-LNM. EVIDENCE LEVEL: 4 TECHNICAL EFFICACY: Stage 2.


Assuntos
Adenocarcinoma , Neoplasias Retais , Adenocarcinoma/diagnóstico por imagem , Adenocarcinoma/cirurgia , Imagem de Difusão por Ressonância Magnética/métodos , Feminino , Humanos , Metástase Linfática/diagnóstico por imagem , Imageamento por Ressonância Magnética , Masculino , Nomogramas , Neoplasias Retais/diagnóstico por imagem , Neoplasias Retais/patologia , Neoplasias Retais/cirurgia , Estudos Retrospectivos
7.
Front Oncol ; 11: 758036, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34778075

RESUMO

OBJECTIVE: This study aims to explore the value of magnetic resonance imaging (MRI) and texture analysis (TA) in the differential diagnosis of ovarian granulosa cell tumors (OGCTs) and thecoma-fibrothecoma (OTCA-FTCA). METHODS: The preoperative MRI data of 32 patients with OTCA-FTCA and 14 patients with OGCTs, confirmed by pathological examination between June 2013 and August 2020, were retrospectively analyzed. The texture data of three-dimensional MRI scans based on T2-weighted imaging and clinical and conventional MRI features were analyzed and compared between tumor types. The Mann-Whitney U-test, χ 2 test/Fisher exact test, and multivariate logistic regression analysis were used to identify differences between the OTCA-FTCA and OGCTs groups. A regression model was established by using binary logistic regression analysis, and receiver operating characteristic curve analysis was carried out to evaluate diagnostic efficiency. RESULTS: A multivariate analysis of the imaging-based features combined with TA revealed that intratumoral hemorrhage (OR = 0.037), log-sigma-20mm-3D_glszm_SmallAreaEmphasis (OR = 4.40), and log-sigma-2-0mm-3D_glszm_SmallAreaHighGrayLevelEmphasis (OR = 1.034) were independent features for discriminating between OGCTs and OTCA-FTCA (P < 0.05). An imaging-based diagnosis model, TA-based model, and combination model were established. The areas under the curve of the three models in predicting OGCTs and OTCA-FTCA were 0.935, 0.944, and 0.969, respectively; the sensitivities were 93.75, 93.75, and 96.87%, respectively; and the specificities were 85.71, 92.86, and 92.86%, respectively. The DeLong test indicated that the combination model had the highest predictive efficiency (P < 0.05), with no significant difference among the three models in differentiating between OGCTs and OTCA-FTCA (P > 0.05). CONCLUSIONS: Compared with OTCA-FTCA, intratumoral hemorrhage may be characteristic MR imaging features with OGCTs. Texture features can reflect the microheterogeneity of OGCTs and OTCA-FTCA. MRI signs and texture features can help differentiate between OGCTs and OTCA-FTCA and provide a more comprehensive and accurate basis for clinical treatment.

8.
AJR Am J Roentgenol ; 216(5): 1335-1343, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33760651

RESUMO

OBJECTIVE. The purpose of our study was to assess the value of combining quantitative dual-energy CT (DECT) parameters with qualitative morphologic parameters for the preoperative prediction of cervical nodal metastasis from papillary thyroid carcinoma (PTC). MATERIALS AND METHODS. Thirty-five patients with pathologically proven PTC underwent single-phase contrast-enhanced DECT before thyroidectomy and cervical lymphadenectomy. Analyses of quantitative DECT parameters and qualitative morphologic features of metastatic and benign lymph nodes (LNs) were independently performed. The diagnostic performances of using only quantitative parameters, only morphologic features, and their combination for predicting cervical nodal metastasis were statistically calculated with ROC curves and logistic regression models. RESULTS. A total of 206 LNs, 80 metastatic and 126 benign, were included. The best single performer in DECT was the normalized iodine concentration in the venous phase, which had low sensitivity (62.5%) but high specificity (85.7%), for diagnosing metastatic cervical LNs. On the other hand, the best single performer in qualitative morphologic parameters was using the criterion of shortest diameter of greater than 5 mm, which had low specificity (69.8%) but high sensitivity (86.3%). Combining these two parameters improved the AUC, sensitivity, and specificity to 0.846, 86.3%, and 72.2%, respectively. The combination of multiple quantitative DECT parameters and all morphologic data further improved AUC, sensitivity, and specificity to 0.878, 87.5%, and 73.8%, respectively, which was significant compared with the use of any single parameter. CONCLUSION. The combination of quantitative DECT parameters with morphologic data improves performance in the preoperative diagnosis of metastatic cervical LNs in patients with PTC.


Assuntos
Linfonodos/diagnóstico por imagem , Metástase Linfática/diagnóstico por imagem , Cuidados Pré-Operatórios/métodos , Câncer Papilífero da Tireoide/patologia , Tomografia Computadorizada por Raios X/métodos , Adulto , Meios de Contraste , Feminino , Humanos , Masculino , Pescoço , Valor Preditivo dos Testes , Intensificação de Imagem Radiográfica/métodos , Imagem Radiográfica a Partir de Emissão de Duplo Fóton/métodos , Sensibilidade e Especificidade
9.
Transl Cancer Res ; 10(10): 4454-4463, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-35116302

RESUMO

BACKGROUND: The number of TB subtypes with irregular masses are increasing year by year, which can easily be confused with lung cancer. This study aimed to explore the value of CT radiomics analysis in differentiating mass-like tuberculosis (TB) from peripheral lung cancer. METHODS: A retrospective analysis of 37 cases with mass-like TB and 41 cases with peripheral lung cancer confirmed by pathology was performed. The performance of conventional CT (7 quantitative and 13 qualitative detection) was analyzed, and 828 texture features extracted by plain CT scan were subjected to dimensionality reduction using the minimal absolute contraction and logistic least absolute shrinkage and selection operator regression. The results were tested according to data distribution types, with differences between the TB and lung cancer groups analyzed by independent-samples t-test, Mann-Whitney test, Pearson chi-square test, or Fisher's exact test. Logistic regression was used to establish a texture feature model, a morphology model and a combined prediction model. The models' diagnostic efficacy was evaluated using receiver operating characteristic (ROC) curves. RESULTS: The comparative analysis between the two groups revealed significant differences in 7 texture parameters (kurtosis, median, skewness, gray-level co-occurrence matrix, gray-level length matrix, gray-level area size matrix, and regional percentage), 4 quantitative parameters [plain scan CT value, arterial phase (AP) CT value, venous phase (VP) CT value, and the difference in CT value between the VP and plain scan], and 8 qualitative CT manifestations (lobular sign, long burr sign, exudation, pleura, necrosis, trachea, vessels, calcifications, and satellite lesions) (P<0.05); logistic regression analysis revealed the area under the ROC curve values of the texture feature, morphology, and combined prediction models to be 0.856, 0.950, and 0.982, respectively (P<0.05). CONCLUSIONS: Combining morphological and radiomics models can effectively and noninvasively improve the efficiency of differentiating mass-like TB from peripheral lung cancer, which is conducive to selecting the appropriate therapy.

10.
Chemosphere ; 257: 127272, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32534299

RESUMO

A hybrid biofilter was established on Fe-C supported carriers aimed to enhance nitrogen removal from polluted water of low Carbon/Nitrogen (C/N) ratio. Effects of organic loadings, hydraulic retention time (HRT), additional electron donor (Fe2+) supplementation and operation mode on the performance of the biofilter were investigated. Results showed that up-flow operation mode was better than down-flow mode in terms of nitrate and total nitrogen (TN) removal at low COD/N. The average removal of NO3--N, NH4+ -N and TN attained 83.1%, 84.7% and 81.2%, respectively, under the conditions of influent COD/NO3--N = 1.5-3.6, HRT = 10 h and up-flow operation. When the biofilter was operated under autotrophic conditions without organic compounds in influent as electron donors, the biofilter achieved a NO3--N removal of 46% and TN removal of 56% depending on the innate electron donors provided by the Fe-C carriers. Supplementation of Fe2+ in influent further promoted autotrophic denitrifying process, and the removal of NO3--N and TN increased to 96.3% and 84.7%, respectively, at the mol ratio of Fe2+/NO3- = 10 and HRT = 10 h. The microbial community was analyzed for the biofilm samples enriched under heterotrophic and autotrophic conditions. The Fe-C biofilter boosted the growth of a large population of mixotrophic denitrifying bacteria including Gallionella, heterotrophic denitrifying bacteria Denitratisoma, and autotrophic denitrifying bacteria Thiobacillus and Thioalkalispira. On the whole, the biofilter coupled with Fe-C micro-electrolysis provides a novel strategy to treat polluted water of low C/N under both heterotrophic and autotrophic conditions.


Assuntos
Reatores Biológicos/microbiologia , Nitrogênio/metabolismo , Processos Autotróficos , Bactérias , Carbono , Desnitrificação , Poluentes Ambientais , Processos Heterotróficos , Nitratos , Águas Residuárias , Água
11.
Acad Radiol ; 27(10): 1406-1415, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32035760

RESUMO

RATIONALE AND OBJECTIVES: To investigate the value of MRI-based features and texture analysis (TA) in the differential diagnosis between ovarian thecomas/fibrothecomas (OTCA/f-TCAs) and uterine fibroids in the adnexal area (UF-iaas). MATERIALS AND METHODS: This retrospective study included 16 OTCA/f-TCA and 37 UF-iaa patients who underwent conventional MRI and DWI between August 2014 and September 2018. Three-dimensional TA was performed with T2-weighted MRI. The clinical, MRI-based and texture features were compared between OTCA/f-TCAs and UF-iaas. Multivariate logistic regression analysis was used for filtering the independent discriminative features and constructing the discriminating model. ROCs were generated to analyse MRI-based features, texture features and their combination for discriminating between the two diseases. RESULTS: Six imaging-based features (ipsilateral ovary detection, arterial period enhancement, lesion components, peripheral cysts, "whorl signs", mean ADCs) and six texture features (Histogram-energy, Histogram-entropy, Histogram-kurtosis, GLCM-energy, GLCM-entropy, and Haralick correlation) were significantly different between OTCA/f-TCAs and UF-iaas (p < 0.05). Multivariate analysis of the MRI-based features revealed that arterial period enhancement (OR = 0.104), peripheral cysts (OR = 16.513), and whorl signs (OR = 0.029) were independent features for discriminating between OTCA/f-TCAs and UF-iaas (p < 0.05). Multivariate analysis of the texture features showed that Histogram-energy and GLCM-energy were independent features for discriminating between OTCA/f-TCAs and UF-iaas (p < 0.05). The area under the curve of imaging-based diagnosis was 0.85, and the combination of imaging-based diagnosis and TA improved the area under the curve to 0.87, with higher accuracy, specificity and sensitivity of 86%, 92%, and 84%, respectively (p < 0.05). CONCLUSIONS: MRI-based features can be useful in differentiating OTCA/f-TCAs from UF-iaas. Furthermore, combining imaging-based diagnosis and TA can improve diagnostic performance.


Assuntos
Leiomioma , Tumor da Célula Tecal , Diagnóstico Diferencial , Feminino , Humanos , Leiomioma/diagnóstico por imagem , Imageamento por Ressonância Magnética , Estudos Retrospectivos , Tumor da Célula Tecal/diagnóstico
12.
J Environ Manage ; 226: 264-269, 2018 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-30121462

RESUMO

Aerobic biodegradation of nitrobenzene (NB) produces nitrophenol (NP), which has stronger toxicity than NB. Anaerobic biodegradation of NB produces aniline (AN), which has weaker toxicity, but is a dead-end product in anaerobic conditions. Accumulation of AN should be overcome by coupling anaerobic and aerobic transformations: NB is transformed to AN in an anaerobic zone of the bioreactor, and AN is then transformed in an aerobic zone. A vertical baffled bioreactor (VBBR) was employed for NB biodegradation with a controlled dissolved oxygen (DO) concentration. NB biodegradation was accelerated by simultaneous anaerobic and aerobic transformations, since AN was biotransformed by a mono-oxygenase reaction. Adding exogenous electron donor (acetate) enhanced NB removals when the DO concentration was ∼0.5 mg/L, because the donor accelerated mono-oxygenations of NB and AN. Coupling anaerobic and aerobic transformations can be a valuable strategy for biodegrading organic compounds that undergo aerobic and anaerobic biotransformations.


Assuntos
Biodegradação Ambiental , Reatores Biológicos , Nitrobenzenos/química , Biotransformação , Nitrofenóis
13.
Biodegradation ; 29(5): 419-427, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-29785468

RESUMO

Pyridine and its heterocyclic derivatives are widely encountered in industrial wastewaters, and they are relatively recalcitrant to biodegradation. Pyridine biodegradation is initiated by two mono-oxygenation reactions that compete for intracellular electron donor (2H). In our experiments, UV photolysis of pyridine generated succinate, whose oxidation augmented the intracellular electron donor and accelerated pyridine biodegradation and mineralization. The first mono-oxygenation reaction always was faster than the second one, because electrons provided by intracellular electron donors were preferentially utilized by the first mono-oxygenase; this was true even when the concentration of 2HP was greater than the concentration of pyridine. In addition, the first mono-oxygenation had faster kinetics because it had higher affinity for its substrate (pyridine), along with less substrate self-inhibition.


Assuntos
Elétrons , Oxigênio/metabolismo , Piridinas/metabolismo , Piridonas/metabolismo , Biodegradação Ambiental , Reatores Biológicos/microbiologia , Cinética , Minerais/metabolismo , Oxirredução , Raios Ultravioleta
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