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In the era of the popularization of the Internet of Things (IOT), analyzing people's daily life behavior through the data collected by devices is an important method to mine potential daily requirements. The network method is an important means to analyze the relationship between people's daily behaviors, while the mainstream first-order network (FON) method ignores the high-order dependencies between daily behaviors. A higher-order dependency network (HON) can more accurately mine the requirements by considering higher-order dependencies. Firstly, our work adopts indoor daily behavior sequences obtained by video behavior detection, extracts higher-order dependency rules from behavior sequences, and rewires an HON. Secondly, an HON is used for the RandomWalk algorithm. On this basis, research on vital node identification and community detection is carried out. Finally, results on behavioral datasets show that, compared with FONs, HONs can significantly improve the accuracy of random walk, improve the identification of vital nodes, and we find that a node can belong to multiple communities. Our work improves the performance of user behavior analysis and thus benefits the mining of user requirements, which can be used to personalized recommendations and product improvements, and eventually achieve higher commercial profits.
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Ultraviolet (UV)/monochloramine (NH2Cl) as an advanced oxidation process was firstly applied for Aspergillus spores inactivation. This study aims to: i) clarify the inactivation and photoreactivation characteristics of UV/NH2Cl process, ii) compared with UV/Cl2 in inactivation efficiency, photoreactivation and energy consumption. The results illustrated that UV/NH2Cl showed better inactivation efficiency than that of UV alone and UV/Cl2, and could effectively control the photoreactivation. For instance, the inactivation rates for Aspergillus flavus, Aspergillus niger and Aspergillus fumigatus in the processes of UV/NH2Cl (2.0 mg/L) was 0.034, 0.030 and 0.061 cm2/mJ, respectively, which were higher than that of UV alone (0.027, 0.026 and 0.024 cm2/mJ) and UV/Cl2 (0.023, 0.026 and 0.031 cm2/mJ). However, there was no synergistic effect for Aspergillus flavus and Aspergillus fumigatus. As for Aspergillus niger, the best synergistic effect can reach 1.86-log10. This may be due to their different resistance to disinfectants, which were related to the size, an outer layer of rodlets (hydrophobins) and pigments. After UV/NH2Cl inactivation, the degree of cell membrane damage and intracellular reactive oxygen species were higher than that of UV alone. UV/NH2Cl had the advantages of high inactivation efficiency and inhibition of photoreactivation, which provides a new entry point for the disinfection of waterborne fungi.
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Cloro , Purificación del Agua , Aspergillus , Cloraminas , Rayos Ultravioleta , Purificación del Agua/métodosRESUMEN
Filamentous fungi can enter drinking water supply systems in various ways, and exist in suspended or sessile states which threatens the health of individuals by posing a high risk of invasive infections. In this study, the biofilms formation kinetics of the three genera of fungal spores, Aspergillus niger (A. niger), Penicillium polonicum (P. polonicum) and Trichoderma harzianum (T. harzianum) isolated from the groundwater were reported, as well as the effects of water quality parameters were evaluated. In addition, the efficiency of low- concentrations of chlorine-based disinfectants (chlorine, chlorine dioxide and chloramine) on controlling the formation of fungal biofilms was assessed. The results showed that the biofilms formation of the three genera of fungi could be divided into the following four phases: induction, exponential, stationary and sloughing off. The optimum conditions for fungal biofilms formation were found to be neutral or weakly acidic at 28 °C with rich nutrition. In fact, A. niger, P. polonicum, and T. harzianum were not observed to form mature biofilms in actual groundwater within 120 hr. Carbon was found to have the maximum effect on the fungal biofilms formation in actual groundwater, followed by nitrogen and phosphorus. The resistance of fungal species to disinfectants during the formation of biofilms decreased in the order: A. niger > T. harzianum > P. polonicum. Chlorine dioxide was observed to control the biofilms formation with maximum efficiency, followed by chlorine and chloramine. Consequently, the results of this study will provide a beneficial understanding for the formation and control of fungal biofilms.
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Desinfectantes , Agua Subterránea , Penicillium , Purificación del Agua , Biopelículas , Cloro , Hongos , Humanos , Hypocreales , CinéticaRESUMEN
OBJECTIVE: To investigate the clinicopathological characteristics and prognosis of incidental prostate cancer (PCa). METHODS: We retrospectively analyzed the clinical data and pathological characteristics of 96 cases of incidental PCa in 580 patients undergoing radical cystectomy and followed them up for prognosis. RESULTS: The incidence rate of incidental PCa was 16.6% (96/580). The patients were 42ï¼90 years old, with a median age of 73 years, 6 (6.2%) ≤60 and 90 (93.8%) over 60 years old. The average maximum diameter of the tumor was about 3.5 cm (range 1.0ï¼9.0 cm). Histologically, 86 (89.6%) of the bladder cancer cases were high-grade invasive urothelial carcinoma (7 with squamous differentiation, 2 with sarcomatoid differentiation, 4 with glandular differentiation, and 1 with plasmacytoid/diffuse variant) and 7 were low-grade urothelial carcinoma, of which 1 case was poorly differentiated neuroendocrine carcinoma and 2 cases were bladder adenocarcinoma, including 1 case of signet ring cell carcinoma. All the PCa cases were classified as the histopathological type of classic acinar adenocarcinoma of the prostate, 67 (69.8%) with a Gleason score ≤ 6, and 29 (30.2%) with a Gleason score ≥ 7. Of the total number of incidental PCa cases, 32 (33.3%) were of clinical significance, and 59 (61.5%) of the patients were followed up for 1ï¼95 (mean 28.7) months, during which 42 (71.2%) survived and 17 (28.8%) died, including 2 deaths due to non-cancer factors. No statistically significant difference was found in the median survival time between the 5 clinically significant and 10 non-clinically significant cases (P = 0.322). CONCLUSIONS: There is a high probability of incidental PCa among bladder cancer patients aged >60 years. Standardized sampling plays an important role in detection of the malignancy. There is only a small proportion of incidental PCa cases with clinical significance, and therefore it affects less the prognosis than bladder cancer.
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Carcinoma de Células Transicionales , Neoplasias de la Próstata , Neoplasias de la Vejiga Urinaria , Adulto , Anciano , Anciano de 80 o más Años , Humanos , Masculino , Persona de Mediana Edad , Neoplasias de la Próstata/epidemiología , Estudios Retrospectivos , Neoplasias de la Vejiga Urinaria/epidemiologíaRESUMEN
Aiming at the problems of low target detection accuracy and high leakage rate of the current traditional weld surface defect detection methods and existing detection models, an improved YOLOv7 pipeline weld surface defect detection model is proposed to improve detection results. In the improved model, a Le-HorBlock module is designed, and it is introduced into the back of fourth CBS module of the backbone network, which preserves the characteristics of high-order information by realizing second-order spatial interaction, thus enhancing the ability of the network to extract features in weld defect images. The coordinate attention (CoordAtt) block is introduced to enhance the representation ability of target features, suppress interference. The CIoU loss function in YOLOv7 network model is replaced by the SIoU, so as to optimize the loss function, reduce the freedom of the loss function, and accelerate convergence. And a new large-scale pipeline weld surface defect dataset containing 2000 images of pipeline welds with weld defects is used in the proposed model. In the experimental comparison, the improved YOLOv7 network model has greatly improved the missed detection rate compared with the original network. The experimental results show that the improved YOLOv7 network model mAP@80.5 can reach 78.6%, which is 15.9% higher than the original model, and the detection effect is better than the original network and other classical target detection networks.
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Lung adenocarcinoma (LUAD) and lung squamous cell carcinoma (LUSC), subtypes of non-small cell lung cancer (NSCLC), exhibit distinct characteristics. The expression and prognostic significance of Protocadherin Gamma Subfamily A, 12 (PCDHGA12) in NSCLC remain unexplored. This study analyzed transcriptomic and genomic datasets from TCGA to investigate PCDHGA12 expression and its prognostic relevance in LUAD and LUSC. We found PCDHGA12 mRNA and protein levels were downregulated in both LUAD and LUSC tissues compared to adjacent non-cancerous tissues, with high PCDHGA12 expression correlating with lower overall survival in LUSC but not in LUAD. GSEA revealed a unique enrichment pattern associated with PCDHGA12 low expression in LUSC, especially in the DNA repair pathway. Co-expression analysis showed associations of PCDHGA12 with focal adhesion and the PI3K-AKT pathway in LUAD, and additionally with ECM-receptor interaction in LUSC. Hub gene prognosis analysis identified genes correlated with prognosis only in LUSC, reflecting PCDHGA12's influence. Mutation analysis linked with PCDHGA12 identified differential mutations in SPTA1, KEAP1, and TNR in LUAD, and a notable NAV3 mutation in LUSC. Additionally, immuno-infiltration analysis reveals a positive correlation between PCDHGA12 expression and immune cell infiltration. Specifically, lower PCDHGA12 expression in LUSC is associated with higher levels of CD8 T cells and DCs, lower levels of Tregs and M0 macrophages, and increased expression of HMGB1 and TNFRSF18. These genetic and immunological differences may account for the significant prognostic disparity of PCDHGA12 levels between LUAD and LUSC. Further experimental studies are essential to validate these associations and investigate potential targeted and immunotherapeutic strategies.
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Adenocarcinoma del Pulmón , Cadherinas , Carcinoma de Células Escamosas , Regulación Neoplásica de la Expresión Génica , Neoplasias Pulmonares , Humanos , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/mortalidad , Neoplasias Pulmonares/inmunología , Pronóstico , Carcinoma de Células Escamosas/genética , Carcinoma de Células Escamosas/mortalidad , Carcinoma de Células Escamosas/inmunología , Cadherinas/genética , Cadherinas/metabolismo , Adenocarcinoma del Pulmón/genética , Adenocarcinoma del Pulmón/mortalidad , Adenocarcinoma del Pulmón/inmunología , Adenocarcinoma del Pulmón/metabolismo , Biomarcadores de Tumor/genética , Mutación , Masculino , Carcinoma de Pulmón de Células no Pequeñas/genética , Carcinoma de Pulmón de Células no Pequeñas/mortalidad , Carcinoma de Pulmón de Células no Pequeñas/metabolismo , Carcinoma de Pulmón de Células no Pequeñas/inmunología , FemeninoRESUMEN
Aggregation is the primary step prior to fungal biofilm development. Understanding the attributes of aggregation is of great significance to better control the emergence of waterborne fungi. In this study, the aggregation of Aspergills spores (A. flavus and A. fumigatus) under various salt, culture medium, and humic acid (HA) conditions was investigated for the first time, and the inactivation via low-pressure ultraviolet (LPUV) upon aggregated Aspergillus spores was also presented. The aggregation efficiency and size of aggregates increased over time and at low salt (NaCl and CaCl2) concentration (10 mM) while decreasing with the continuous increase of salt concentration (100 and 200 mM). Increasing the concentration of culture medium and HA promoted the aggregation of fungal spores. Spores became hydrated, swelled, and secreted more viscous substances during the growth period, which accelerated the aggregation process. Results also suggested that fungal spores aggregated more easily in actual water, posing a high risk of biohazard in real-life scenarios. Inactivation efficiency by LPUV decreased with higher aggregation degrees due to the protection from the damaged spores on the outer layer and the shielding of pigments in the cell wall. Compared to chlorine-based disinfection, the aggregation resulted in the extension of shoulder length yet neglectable change of inactivation rate constant under LPUV treatment. Further investigation of cell membrane integrity and intracellular reactive oxygen species was conducted to elucidate the difference in mechanisms between various techniques. This study provides insight into the understanding and controlling of the aggregation of fungal spores.
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Desinfección , Purificación del Agua , Desinfección/métodos , Cloro/farmacología , Aspergillus , Esporas Fúngicas , Agua , Rayos UltravioletaRESUMEN
BACKGROUND: Non-small Cell Lung Cancer (NSCLC) makes up about 85% of lung cancer cases, mainly adenocarcinoma and squamous cell carcinoma. Recently, PD-1 inhibitors have become crucial in NSCLC treatment, significantly enhancing survival for some. However, side effects, like skin reactions and hematotoxicity, limit their use, with drug-induced TEN and immunotherapy-induced agranulocytosis as severe adverse effects. CASE PRESENTATION: Herein, we have reported the case of a 75-year-old male diagnosed with metastatic Lung Squamous cell Carcinoma (LUSC) in the left lung. He received first-line treatment with one cycle of tislelizumab in combination with nab-paclitaxel and carboplatin, after which he developed Toxic Epidermal Necrolysis (TEN) and granulocytopenia. To address these two serious immune-related Adverse Events (irAEs), the patient was administered methylprednisolone in combination with gamma globulin for TEN and dexamethasone in combination with G-CSF for agranulocytosis. Antibiotics were also administered according to the patient's medication regimen. After treatment, the patient recovered and was discharged from the hospital. It was also noted that the lung tumor condition improved. CONCLUSION: Effective management of severe immune-related side effects from tislelizumab, including TEN and agranulocytosis, can be partly achieved through steroids, gamma globulin, GCSF, and antibiotics. This strategy not only alleviates these adverse effects, but also potentially improves tumor conditions, highlighting the crucial role of vigilant monitoring and management in immunotherapy.
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OBJECTIVE: To investigate the association of human papillomavirus (HPV) in the pubic hair follicles of males with HPV infection in their female sexual partners. METHODS: We included in this study 21 female patients with HPV infection, including 8 cases of cervical cancer, 5 cases of atypical cervical hyperplasia, 5 cases of cervical condyloma, and 3 cases with unidentified causes. We also enlisted 52 men without visible condyloma acuminatum in the external genitalia as healthy controls. We detected HPV in the pubic hair follicles of the female patients' male sexual partners and the healthy male controls by PCR and reverse hybridization in situ. RESULTS: HPV positive was found in 6 (28.6%) of the 21 women's male partners, in whom the HPV types were correspondent situ. to those of the female patients. CONCLUSION: HPV in the pubic hair follicles of men might be one of the causes of HPV-related cervical lesions in their female sexual partners.
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Folículo Piloso/virología , Infecciones por Papillomavirus/transmisión , Infecciones por Papillomavirus/virología , Enfermedades del Cuello del Útero/virología , Adolescente , Adulto , Estudios de Casos y Controles , Femenino , Genitales Masculinos/virología , Humanos , Masculino , Persona de Mediana Edad , Papillomaviridae , Parejas Sexuales , Neoplasias del Cuello Uterino/virología , Adulto JovenRESUMEN
Recently, the contamination of fungi in water has aroused widespread concern, which will pose a threat to water quality and safety, and raise diseases risk in the immunocompromised individuals. In this review, the characteristics and different physiological state of fungi in water are summarized. A comprehensive evaluation of the control efficiency and mechanism of waterborne fungi by the commonly used disinfection methods is provided as well. During the disinfection processes of chlorine, chlorine dioxide, chloramine and advanced disinfection processes (ADPs) such as O3-based ADPs and UV-based ADPs, the fungal spores firstly lost their culturability, followed by membrane integrity, and the intracellular reactive oxygen species level increased at the same time, eventually the fungal spores were completely inactivated. The security strategies of drinking water against the contamination of fungi are also discussed in terms of water sources, water treatment plants and pipe network. Finally, future researches need to be explored are proposed: the rapid detection methods, the production laws and control of mycotoxin, and the outbreak conditions of fungi in water. Specifically, exploring efficient, safe and economical technologies, especially ADPs, is still the main direction in the disinfection of fungi in future studies. This review can offer a comprehensive understanding on the occurrence and control of fungi in water to fill the knowledge gap and provide guidance for the future research.
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Desinfectantes , Agua Potable , Purificación del Agua , Humanos , Hongos , Desinfección , Esporas Fúngicas , CloroRESUMEN
PURPOSE: Hepatocellular carcinoma (HCC) with portal vein tumor thrombus (PVTT) is associated with a poor prognosis for HCC patients. Herein we aimed to establish a scoring system to predict the risk of PVTT formation in hepatitis B virus (HBV)-associated HCC. METHODS: A total of 848 patients from the Henan Province Traditional Chinese Medicine (TCM) Hospital with HCC were included in the study. Among them, 403 with and 445 without PVTT were retrospectively analyzed to identify the risk factors for PVTT formation, using a novel scoring system to predict the occurrence of PVTT in HBV-associated HCC patients. The scoring system was validated using clinical data from the First Affiliated Hospital of Henan University of TCM. Significant findings: The Cox proportional-hazard regression model revealed that gender, tumor size, the neutrophil-lymphocyte ratio, and alpha-fetoprotein and C-reactive protein concentrations were dependent clinical prognostic factors for PVTT, which were included in the final scoring model for PVTT prediction (AUC, 0.858; 95% CI: 0.832 to 0.881). The scoring model ranked HCC patients into 3 risk grades. A sensitivity analysis for validation of the scoring system was performed on 489 patients with HBV-related HCC. The proportion of patients in each grade was not significantly different. CONCLUSIONS: The study established a risk warning system for PVTT prediction in HCC patients. More substantial clinical data will be necessary to confirm these findings.
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A facile covalent assembly strategy is proposed for the preparation of superhydrophobic COF-stabilized MXene separation membranes. Ultra-high separation fluxes of up to 54 280 L m-2 h-1 and 643 200 L m-2 h-1 bar-1 are obtained for emulsified water-in-oil mixtures by adopting gravity and external pressure, respectively. Moreover, the challenges of easy swelling and oxidation properties of MXene have been effectively overcome via the COF-stabilized mechanism.
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Waterborne fungi pose a potential threat to water supply safety due to their high resistance to disinfectants. Peracetic acid, as a promising alternative disinfectant to chlorine, has attracted increasing attention in water treatment. In this study, the inactivation of two dominant fungal species (Aspergillus niger and Aspergillus flavus) by sequential application of peracetic acid and ultraviolet (PAA-UV/PAA) was reported for the first time. Results revealed that the pre-exposure of PAA could facilitate the subsequent process of UV/PAA combination and shorten the lag phase in fungi inactivation. After 10 min of PAA pre-exposure, PAA-UV/PAA achieved 3.03 and 2.40 log inactivation of Aspergillus niger and Aspergillus flavus, which were 2- and 4.3-fold higher than that of direct UV/PAA under the same UV and PAA doses. PAA-UV/PAA disinfection also exhibited a stronger regrowth inhibition for incompletely inactivated fungal spores than direct UV/PAA. The increase of pH (5.0-9.0) and humic acid concentration (1.0-5.0 mg L - 1) showed an inhibitory effect on PAA-UV/PAA inactivation, but PAA-UV/PAA was more adaptable in a wide pH range and the presence of humic acid compared to direct UV/PAA. The more severe cell membrane damage and higher reactive oxygen species level in PAA-UV/PAA were evidenced for the first time by flow cytometry. The increased hydroxyl radical generation and higher synergism were primarily responsible for inactivation improvement. This study enhances the further understanding of the PAA-UV/PAA process, and the findings are expected to promote the development of PAA as a promising disinfectant for effective fungi control.
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Desinfectantes , Purificación del Agua , Ácido Peracético/farmacología , Esporas Fúngicas , Sustancias Húmicas , Rayos Ultravioleta , Desinfectantes/farmacología , Desinfección/métodosRESUMEN
Performic acid (PFA) has received increasing attention in water disinfection due to its high disinfection efficiency and fewer formation of disinfection by-products. However, the inactivation of fungal spores by PFA has not been investigated. In this study, the results showed that the log-linear regression plus tail model adequately described the inactivation kinetic of fungal spores with PFA. The k values of A. niger and A. flavus with PFA were 0.36 min-1 and 0.07 min-1, respectively. Compared to peracetic acid, PFA was more efficient in inactivating fungal spores and caused more serious damage on cell membrane. Compared to neutral and alkaline conditions, acidic environments demonstrated a greater inactivation efficiency for PFA. The increase of PFA dosage and temperature had a promoting effect on the inactivation efficiency of fungal spores. PFA could kill the fungal spores by damaging cell membrane and penetration of cell membranes. In real water, the inactivation efficiency declined as a result of the existence of background substances such as dissolved organic matter. Moreover, the regrowth potential of fungal spores in R2A medium were severely inhibited after inactivation. This study provides some information for PFA to control fungi pollution and explores the mechanism of PFA inactivation.
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Desinfectantes , Ácido Peracético , Desinfectantes/análisis , Agua , Esporas Fúngicas , Desinfección/métodosRESUMEN
Recently, the viabilities changes of fungal spores in the water supply system during different disinfection processes have been revealed. SYBR Green I (SG), a nucleic acid stain, its fluorescence intensity is correlated with the amount of double-stranded DNA. This study established a new method through successive SG-SG-PI staining (PI: Propidium Iodide) with flow cytometry (FCM). It could successfully distinguish DNA damage and membrane damage of fungal spores, clearly elucidating the intrinsic disinfection mechanism during the chemical disinfection. This method was briefly described as follows: firstly, (1) the fungal spores were stained with SG and washed by centrifugation; and then, (2) the washed spores were treated with disinfectants and terminated; after that, (3) the disinfected spores were re-stained with SG and analyzed by FCM; finally, (4) the SG re-stained spores were stained with PI and analyzed by FCM. The percentages of spores with DNA damage and membrane damage were determined by the fluorescence intensity obtained from steps (3) and (4), respectively. The repeatability and applicability of this developed method were confirmed. It was further applied to explore the inactivation mechanism during chlorine-based disinfection, and results demonstrated that chloramine attacked the DNA more seriously than the membrane, while chlorine and chlorine dioxide worked in a reverse way.
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Desinfectantes , Desinfección , Cloro , ADN , Desinfectantes/farmacología , Citometría de Flujo/métodos , Esporas FúngicasRESUMEN
The disinfection of pathogenic microorganisms in water treatment by peracetic acid (PAA)-based advanced oxidation processes (AOPs) has been gaining increasing concern. In this work, the inactivation mechanism, influencing factors and regrowth of two pathogenic Aspergillus species in the system of CuO-activated PAA were studied for the first time. The k values of A. niger and A. flavus inactivated by PAA/CuO system were 3.9 and 2.1-fold higher than those inactivated by PAA alone. PAA concentration and CuO dose were positively correlated with the inactivation efficiency, while humic acid and pH were negatively correlated. The main active species that contributed to the inactivation of fungal spores in PAA/CuO system were â¢OH, CH3C(O)OO⢠and 1O2. PAA/CuO system had more intense oxidative stimulation and more serious damage to fungal spores according to the analysis of cell membrane integrity and intracellular ROS levels. In addition, the PAA/CuO system was less impacted by the water matrix and kept a good inactivation efficiency in real water samples. The regrowth potential of fungal spores after disinfection was also reduced in PAA/CuO system so as to avoid the risk of biological regrowth. This study provides a feasible PAA-based advanced oxidation method for activating PAA and inactivating fungal spores.
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Ácido Peracético , Purificación del Agua , Cobre , Desinfección/métodos , Cinética , Ácido Peracético/farmacología , Esporas FúngicasRESUMEN
Melanin is a critical component of fungal cell wall which protect fungi from adverse environmental tress. However, the role of melanin for fungi during the disinfection with chlorine-based disinfectants has not been elucidated. The results showed that the inactivation rate constants of Aspergillus niger with chlorine and chlorine dioxide decreased from 0.08 to 2.10 min-1 to 0 after addition of 0.32 mg/L melanin. The results indicated addition of extracted fungal melanin inhibited the inactivation efficiency of chlorine and chlorine dioxide. In contrast, the k of Aspergillus niger after inactivation with monochloramine ranged from 1.50 to 1.78 min-1 after addition of melanin which indicated effect of melanin on the inactivation efficiency of monochloramine was negligible. In addition, the extracted fungal melanin exhibited high reactivity with chlorine and chlorine dioxide but very low reactivity with monochloramine. The different inactivation mechanisms of chlorine-based disinfectants and different reactivity of melanin with chlorine-based disinfectants led to the different protective mechanism of melanin for A. niger and A. flavus spores against disinfection with chlorine-based disinfectants. The chlorine and chlorine dioxide appeared to react with functional groups of melanin in cell wall of spores, so sacrificial reactions between melanin and disinfectants decreased the available disinfectants and limited the diffusion of disinfectants to the reactive site on cell membrane, which led to the decrease of the disinfection efficiency for chlorine and chlorine dioxide. The monochloramine could penetrate into cell and damage DNA without the effect of melanin due to its strong penetration and low reactivity with melanin. Our results systematically demonstrate the protective roles of melanin on the fungal spores against chlorine-based disinfectants and the underlying mechanisms in resisting the environmental stress caused by chlorine-based disinfectants, which provides important implications for the control of fungi, especially for fungi producing melanin.
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Cloro , Desinfectantes , Aspergillus , Aspergillus flavus , Aspergillus niger , Cloraminas , Cloruros , Cloro/farmacología , Compuestos de Cloro , ADN , Desinfectantes/farmacología , Desinfección/métodos , Melaninas , ÓxidosRESUMEN
In this work, sequential applications of light-emitting diodes (UV-LEDs) with two wavelengths and chlorine (Cl2) were performed for fungal spores disinfection: UV-Cl2, Cl2-UV, UV/Cl2-UV, UV-UV/Cl2, Cl2-UV/Cl2-Cl2. Overall comparisons of the sequential processes with respect to the inhibitory effect on photoreactivation were also evaluated. According to the evaluation of culturability and membrane permeability, inactivation of fungal spores by UV was not enhanced by prior or post exposure to Cl2, but in the UV/Cl2 process with pre or post UV treatment, the inactivation efficiency was greatly enhanced. Take P. polonicum for example, pre-treatments by UV265 and UV280 (40 mJ/cm2) caused the log count reduction (LCR) of 1.05 log and 0.95 log, then the followed UV265/Cl2 and UV280/Cl2 at the same UV fluence caused additional LCR of 1.80 log and 2.00 log. The permeabilization of P. polonicum was also accelerated in the processes of UV/Cl2-UV and UV-UV/Cl2, especially at the wavelength of 280 nm. In the sequential processes, especially those containing UV/Cl2 or at the wavelength of 280 nm, could promote the formation of intracellular reactive oxygen species (ROS), thus leading to more severe damage to the spores as reflected in the culturability reduction, membrane permeability and inhibition of photoreactivation.
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Cloro , Purificación del Agua , Desinfección , Esporas Fúngicas , Rayos UltravioletaRESUMEN
The contamination of fungi in water supply systems poses great risks to environment and human health. In this work, UV light-emitting diodes (UV-LEDs)-based advanced disinfection processes (ADPs) including UV-LEDs/hydrogen peroxide (H2O2), UV-LEDs/persulfate (PS) and UV-LEDs/peroxymonosulfate (PMS), were adopted for waterborne fungal spores inactivation. Overall comparisons of the UV-LEDs-based ADPs with respect to the control efficiency of photoreactivation and energy consumption were also evaluated. Results showed that culturability reduction of the fungal spores treated by UV-LEDs was not enhanced with the addition H2O2, PMS, and PS according to the results of heterotrophic plate counts and reaction rate constants; A. niger was expected to have higher UV resistance followed by T. harzianum and P. polonicum. However, UV-LEDs-ADPs inactivation, especially at the wavelengths of 280 and 265/280 nm, could accelerate the permeabilization of fungal spores as characterized by flow cytometry. Take P. polonicum for example, the percentage of membrane permeabilized spores was 98.0%, 98.7%, 97.6% and 82.6% after treatment by UV280/H2O2, UV280/PS, UV280/PMS and UV280 alone, respectively at the fluence of 100 mJ/cm2. The direct attack of free radicals in the processes of UV-LEDs-ADPs further enhanced the membrane damage and lowered the photoreactivation level, thus improved the inactivation efficiency. UV-LEDs/H2O2 was considered as an effective process in the disinfection of fungal spores with the advantages of enhancing the damage of membrane, inhibiting photoreactivation and comparable energy consumption compared with UV-LEDs alone.
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Desinfección , Purificación del Agua , Humanos , Peróxido de Hidrógeno , Cinética , Esporas Fúngicas , Rayos UltravioletaRESUMEN
Peracetic acid (PAA) can effectively inactivate fungi in water, while may pose a potential risk of regrowth after disinfection. The inactivation kinetic and mechanism of fungal spores by combined UV and PAA (UV/PAA) was investigated in this study. The results showed that synergistic factor of the inactivation of A. niger and A. flavus was 1.44 and 1.37, which indicated significant synergistic effect of UV/PAA. The k of A. niger and A. flavus was similar at pH 5.0 and 7.0, while decreased 60.00% and 39.13% at pH 9.0 compared with that at pH 7.0. The effect of HA concentration on the inactivation efficiency of fungal spores by UV/PAA was negative, while the effect of PAA concentration was positive. The membrane permeabilized cell of A. niger and A. flavus caused by UV/PAA was 17.0% and 31.7%, which was higher than that caused by PAA and UV alone. The changes of morphology of fungal spores and the leakage of intracellular material indicated that the damage of cell structure caused by UV/PAA system was more serious than that of UV or PAA alone. In addition, the four parts that contributed in UV/PAA system was in the following order: UV > radical > PAA > synergistic effect. The inactivation efficiency of combined UV and chlorine (UV/Cl2) was higher than that of UV/PAA. Furthermore, the typical order of the inactivation efficiency in different matrix was: phosphate buffer solution > surface water > secondary effluent. The regrowth potential of fungal spores after UV/PAA treatment was significantly lower than that by PAA alone, indicating that UV/PAA could decrease the microbial regrowth potential after PAA disinfection alone.