RESUMO
Pesticides represent one of the largest intentional inputs of potentially hazardous compounds into agricultural soils. However, as an important vegetable producing country, surveys on pesticide residues in soils of vegetable production areas are scarce in China. This study presented the occurrence, spatial distribution, correlation between vegetable types and pesticides, and ecological risk evaluation of 94 current-use pesticides in 184 soil samples from vegetable production areas of Zhejiang province (China). The ecological risks of pesticides to soil biota were evaluated with toxicity exposure ratios (TERs) and risk quotient (RQ). The pesticide concentrations varied largely from below the limit of quantification to 20703.06 µg/kg (chlorpyrifos). The situation of pesticide residues in Jiaxing is more serious than in other cities. Soils in the vegetable areas are highly diverse in pesticide combinations. Eisenia fetida suffered exposure risk from multiple pesticides. The risk posed by chlorpyrifos, which exhibited the highest RQs at all scenarios, was worrisome. Only a few pesticides accounted for the overall risk of a city, while the other pesticides make little or zero contribution. This work will guide the appropriate use of pesticides and manage soil ecological risks, achieving green agricultural production.
Assuntos
Clorpirifos , Resíduos de Praguicidas , Praguicidas , Poluentes do Solo , Praguicidas/toxicidade , Praguicidas/análise , Resíduos de Praguicidas/toxicidade , Resíduos de Praguicidas/análise , Solo/química , Verduras , Monitoramento Ambiental , Medição de Risco , Poluentes do Solo/toxicidade , Poluentes do Solo/análiseRESUMO
Information processing functions are essential for organisms to perceive and react to their complex environment, and for humans to analyze and rationalize them. While our brain is extraordinary at processing complex information, winner-take-all, as a type of biased competition is one of the simplest models of lateral inhibition and competition among biological neurons. It has been implemented as DNA-based neural networks, for example, to mimic pattern recognition. However, the utility of DNA-based computation in information processing for real biotechnological applications remains to be demonstrated. In this paper, a biased competition method for nonlinear manipulation and analysis of mixtures of DNA sequences was developed. Unlike conventional biological experiments, selected species were not directly subjected to analysis. Instead, parallel computation among a myriad of different DNA sequences was carried out to reduce the information entropy. The method could be used for various oligonucleotide-encoded libraries, as we have demonstrated its application in decoding and data analysis for selection experiments with DNA-encoded chemical libraries against protein targets.
Assuntos
Redes Neurais de Computação , Neurônios , Humanos , Neurônios/fisiologia , Computadores Moleculares , DNA/genética , DNA/química , EncéfaloRESUMO
To clarify the residue behavior and possible dietary risk of abamectin in fresh corn, bitter melon, and Fritillaria, a method was developed for the simultaneous determination of abamectin residues in fresh corn, bitter melon, and Fritillaria by QuEChERS (quick, easy, cheap, effective, rugged, safe) ultra-performance liquid chromatography-tandem mass spectrometry. The mean recovery of abamectin in fresh corn, bitter melon, and Fritillaria was 86.48%-107.80%, and the relative standard deviation was 2.07%-10.12%. The detection rates of abamectin residues in fresh corn, bitter melon, and Fritillaria were 62.50%, 87.50%, and 80.00%, respectively. The residues of abamectin in fresh corn, bitter melon, and Fritillaria were not more than 0.020, 0.019, and 0.087 mg/kg, respectively. Based on these results, dietary risk assessment showed that the risk content of abamectin residues in long- and short-term dietary exposure for Chinese consumers was 61.57% and 0.41%-1.11%, respectively, indicating that abamectin in fresh corn, bitter melon, and Fritillaria in the market would not pose a significant risk to consumers.
Assuntos
Fritillaria , Ivermectina/análogos & derivados , Momordica charantia , Resíduos de Praguicidas , Momordica charantia/química , Zea mays , Medição de Risco , Resíduos de Praguicidas/análiseRESUMO
OBJECTIVES: Nursing factors have been found to be associated with a reduction in readmission rates. Nevertheless, few attentions have been given to the effect of nursing factors on nursing home (NH) residents. This study was to assess the impact of nursing factors on the hospital readmissions and length of stay (LOS) of the elderly residents from the NH. STUDY DESIGN: This was a cross-sectional study. METHODS: Data were extracted from the NH of the LTCFocus.org data set between 2011 and 2018. The study included residents aged ≥55 years who were admitted to NH in the United States, following a hospitalization event. The nursing factors included facility-level data elements and medical care personnel. An unsupervised machine learning algorithm (K-means) was used to cluster NH according to readmission rate and LOS. Multivariate logistic regression analysis was performed. RESULTS: This study consisted of 107,000 NH-year observations. The median readmission rate was 17%, with a median LOS was 28.00 days. Three clusters were identified: cluster 1 was a high readmission rate with high LOS, cluster 2 was a low readmission rate with low LOS, and cluster 3 was a high readmission rate with low LOS. Multifacility and admission/bed were associated with a reduction in readmission rate and LOS in both cluster 1 vs cluster 2 and cluster 3 vs cluster 2. The special care unit and registered nurses' ratio were associated with decreased readmission rate and LOS in cluster 1 vs cluster 2. Total beds and Alzheimer unit decreased the readmission rate and LOS, whereas certified nursing assistant increased the readmission rate and LOS in cluster 3 vs cluster 2. NH for profit was associated with elevated readmission rate and LOS in cluster 1 vs cluster 2 and decreased readmission rate and LOS in cluster 3 vs cluster 2. Based on the subgroup analysis, the certified nursing assistant decreased readmission rate and LOS in cluster 1 vs cluster 2 and increased readmission rate and LOS in cluster 3 vs cluster 2 (all P < 0.005). CONCLUSION: This study indicates the importance of the improvement of nurse number and level and the inputs of facility characteristics in NH.
Assuntos
Casas de Saúde , Humanos , Idoso , Estudos TransversaisRESUMO
A rapid, efficient, simple, and high-throughput method for the simultaneous determination of 108 pesticide residues in three traditional Chinese medicines (TCMs) was established, comprising an improved QuEChERS method in combination with HPLC-MS/MS based on mixed samples. A quantity of 10 mL of acetonitrile was used as extraction solvent, and 10 mg of amino-modified multi-walled carbon nanotubes (MWCNTs-NH2) and 150 mg of anhydrous magnesium sulfate (MgSO4) were selected as sorbents for dispersive solid phase extraction. The performance of the method was verified according to the analytical quality control standards of SANTE/11813/2017 guidelines. With good linearity (R2 > 0.9984) in the range of 2−200 µg/L for all pesticides in the selected matrices, and good accuracy, precision, and high sensitivity, the recoveries were in the range of 70−120% for more than 95% of the pesticides, with a relative standard deviation (RSD) of less than 16.82% for all. The limit of detection (LOD) and limit of quantification (LOQ) of the method were 0.01−3.87 µg/kg and 0.07−12.90 µg/kg, respectively, for Fritillaria thunbergii Miq (F. thunbergii), Chrysanthemum Morifolium Ramat (C. morifolium), and Dendrobium officinale Kimura et Migo (D. officinale). The method was successfully applied to 60 batches of actual samples from different regions.
Assuntos
Nanotubos de Carbono , Resíduos de Praguicidas , Praguicidas , Resíduos de Praguicidas/análise , Cromatografia Líquida de Alta Pressão , Espectrometria de Massas em Tandem/métodos , Nanotubos de Carbono/química , Extração em Fase Sólida/métodos , ChinaRESUMO
The massive use of pesticides has brought great risks to food and environmental safety. It is necessary to develop reliable analytical methods and evaluate risks through monitoring studies. Here, a method was used for the simultaneous determination of flupyradifurone (FPF) and its two metabolites in fresh ginseng, dried ginseng, ginseng plants, and soil. The method exhibited good accuracy (recoveries of 72.8-97.5%) and precision (relative standard deviations of 1.1-8.5%). The field experiments demonstrated that FPF had half-lives of 4.5-7.9 d and 10.0-16.9 d in ginseng plants and soil, respectively. The concentrations of total terminal residues in soil, ginseng plants, dried ginseng, and ginseng were less than 0.516, 2.623, 2.363, and 0.641 mg/kg, respectively. Based on these results, the soil environmental risk assessment shows that the environmental risk of FPF to soil organisms is acceptable. The processing factors for FPF residues in ginseng were 3.82-4.59, indicating that the concentration of residues increased in ginseng after drying. A dietary risk assessment showed that the risk of FPF residues from long-term and short-term dietary exposures to global consumers were 0.1-0.4% and 12.07-13.16%, respectively, indicating that the application of FPF to ginseng at the recommended dose does not pose a significant risk to consumers.
Assuntos
Panax , Resíduos de Praguicidas , Poluentes do Solo , 4-Butirolactona/análogos & derivados , Monitoramento Ambiental/métodos , Panax/química , Resíduos de Praguicidas/análise , Piridinas , Medição de Risco , Solo/química , Poluentes do Solo/análiseRESUMO
Phase separation and transitions among different molecular states are ubiquitous in living cells. Such transitions can be governed by local equilibrium thermodynamics or by active processes controlled by biological fuel. It remains largely unexplored how the behavior of phase-separating systems with molecular transitions differs between thermodynamic equilibrium and cases in which the detailed balance of the molecular transition rates is broken because of the presence of fuel. Here, we present a model of a phase-separating ternary mixture in which two components can convert into each other. At thermodynamic equilibrium, we find that molecular transitions can give rise to a lower dissolution temperature and thus reentrant phase behavior. Moreover, we find a discontinuous thermodynamic phase transition in the composition of the droplet phase if both converting molecules attract themselves with similar interaction strength. Breaking the detailed balance of the molecular transition leads to quasi-discontinuous changes in droplet composition by varying the fuel amount for a larger range of intermolecular interactions. Our findings showcase that phase separation with molecular transitions provides a versatile mechanism to control properties of intracellular and synthetic condensates via discontinuous switches in droplet composition.
Assuntos
Termodinâmica , Transição de Fase , TemperaturaRESUMO
The dissipation and residue of validamycin A in grapes were investigated under field conditions. An ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method for the determination of validamycin A in grapes was established and validated. Methanol and water (90/10, v/v) were used for validamycin A extraction and purification used MCX solid-phase extraction cartridges. The average recoveries of validamycin A in grapes at 0.01, 0.50, and 5.0 mg/kg levels were between 83.8 and 91.4%, with relative standard deviations of 2.3-3.0%. The half-lives of validamycin A in grape were 4.4-6.1 days. The terminal residues in grapes over a range of harvest times (7, 14, and 21 days) were no more than 0.73 mg/kg. According to Chinese consumption data, the risk quotient (RQ) of validamycin A was 3.22%, demonstrating a low risk to consumers. The current study may offer guidance for validamycin A use and could aid the government in determining the maximum residue level (MRL) values for validamycin A in grapes.
Assuntos
Frutas/química , Fungicidas Industriais/análise , Inositol/análogos & derivados , Resíduos de Praguicidas/análise , Vitis/química , Cromatografia Líquida de Alta Pressão , Exposição Dietética/análise , Contaminação de Alimentos/análise , Humanos , Inositol/análise , Medição de Risco , Extração em Fase Sólida , Espectrometria de Massas em TandemRESUMO
Although the carbendazim is widely used to manage spot blight in celery cultivation, information on residues identified is of interest. In this study, we examined the dissipation and residual amounts of carbendazim in celery and soil under different cultivation methods when using the suggested dose and ten times of that and the bioconcentration factor of carbendazim for celery. The results showed that when celery leaves were sprayed with the suggested dose, the half-lives in a celery field and greenhouse were 2.75 days and 3.29 days, respectively. When the soil matrix was sprayed with the recommended dose before cultivation, the half-lives of carbendazim residues were 16.86 days and 11.97 days. We also conducted a long-term dietary risk assessment using the corresponding criteria. The results showed that, in China, the use of carbendazim at a dose of 0.022 g/m2 is safer and more reasonable when the harvest interval is 28 days.
Assuntos
Apium , Resíduos de Praguicidas , Poluentes do Solo , Benzimidazóis , Carbamatos/análise , Carbamatos/toxicidade , China , Meia-Vida , Resíduos de Praguicidas/análise , Medição de Risco , Solo , Poluentes do Solo/análiseRESUMO
Microplastics (MPs) as a type of emerging contaminant in the environment have attracted extensive attentions in recent years, and understanding the impacts of MPs on soil biodiversity and functioning are thus increasingly urgent. Nevertheless, few studies were performed to investigate potential effects of MPs on decay of soil organic pollutants in particular pesticides and enzyme activities. Herein, three types of MPs including polystyrene fragments (PS-50) and polyvinyl chloride beads (PVC-42000 and PVC-10) were added to soil at environmentally relevant concentrations (0.2 and 1.0%) to study their impacts on dissipation of thiacloprid and activities of urease, acid phosphatase, invertase and catalase. MPs exhibited negligible impacts on thiacloprid dissipation regardless of MPs type and content, being probably attributed to the unaltered bioavailability of thiacloprid in soil even after an addition of MPs, which was documented by using the hydroxypropyl-ß- cyclodextrin (HPCD) extraction method. Batch sorption experiments also exhibited the comparable adsorption capacity of thiacloprid to soil with and without MPs, along with Kf valuses of 3.44-3.77. Besides, MPs exerted negligible effects on enzyme activities of soil. Taken together, this study showed negligible impacts of MPs at environmentally relevant concentrations on thiacloprid dissipation and enzyme activity, expanding our knowledge on impacts of MPs at the environmentally relevant concentrations on pesticide dissipation in soil.
Assuntos
Poluentes do Solo , Solo , Microplásticos , Neonicotinoides , Plásticos , Poluentes do Solo/análise , TiazinasRESUMO
Effective and safe acaricides based on scientific data are needed for that no chemical acaricides has been registered for the control of two-spotted spider mite in strawberry crops in China. To identify suitable acaricides, the efficacy, persistence, and toxicity of eight acaricides (hexythiazox, fenpyroximate, chlorfenapyr, propargite, etoxazole, bifenazate, spirodiclofen, and pyridaben) on greenhouse strawberries were tested. The eight acaricides were ranked, from highest average efficacy at the recommended dosage to lowest, as follows: etoxazole >â¯bifenazate >â¯fenpyroximate >â¯propargite >â¯spirodiclofen >â¯pyridaben >â¯hexythiazox>â¯chlorfenapyr. The average recoveries of the eight acaricides at the spiking levels of 0.05 and 0.5â¯mg/L ranged from 72.4% to 108.1% (relative standard deviation, 1.3-8.8%). The concentrations of hexythiazox, fenpyroximate, etoxazole, bifenazate, spirodiclofen, and pyridaben at 5 days after application were lower than the maximum residue limits (MRLs) specified by China, the European Union (EU), the Codex Alimentarius Commission, and Japan, but those of chlorfenapyr and propargite residues were 8.8 and 1.9 times higher than the MRLs in the EU. Only propargite posed a high chronic dietary risk to humans. Pyridaben and chlorfenapyr showed unacceptable ecotoxicology risks for honeybees (hazard quotient values of >â¯50). The recommended acaricides to control spider mites in greenhouse-grown strawberry crops are etoxazole, bifenazate, fenpyroximate, spirodiclofen, and hexythiazox based on the efficacy, persistence and toxicity.
Assuntos
Acaricidas/toxicidade , Contaminação de Alimentos/análise , Fragaria/metabolismo , Tetranychidae/efeitos dos fármacos , Adulto , Animais , Abelhas , China , Fragaria/parasitologia , Humanos , Medição de Risco , Tetranychidae/fisiologiaRESUMO
Methylated vegetable oil adjuvants can enhance initial deposition and decrease the required dosages of pesticides sprayed on plants, so an oil adjuvant mixed with fungicides were used to prevent and control gray mold in greenhouse strawberry. As the persistence and dietary exposure risks from fungicides on strawberries after using adjuvants have not been assessed, the efficacy, dissipation and safety of pyrimethanil and boscalid in the presence and absence of a methylated vegetable oil adjuvant were evaluated. To better describe the actual use of fungicides in greenhouse strawberry, twice repeated application of fungicides were conducted follower by an optimized QuEChERS pre-treatment method. When applied at 60% of their recommended dosages with the adjuvant, the efficacy of pyrimethanil and boscalid for gray mold was similar to that shown by the treatment of 100% fungicides in absence of the adjuvant based on Duncan's Multiple-Range test, and their average residues increased to 89.0% and 89.3%, respectively. The adjuvant enhanced the accumulation effect of pyrimethanil residue by 31.7% after repeated applications, and the half-lives were similar (5.2 and 4.2 d). The adjuvant had comparable accumulation effects (1.75 and 1.83) and similar half-lives (5.4 and 5.5 d) for boscalid. In absence of adjuvant, the risk quotients (RQs) of pyrimethanil (0.41 and 0.33) and boscalid (0.49 and 0.63) after twice applications at pre-harvest interval were lower than 1. Adding the methylated vegetable oil adjuvant to fungicides would result in unprolonging half-life and acceptably low dietary exposure risk on strawberries, but lower dosage of fungicides were used.
Assuntos
Compostos de Bifenilo/administração & dosagem , Fragaria , Fungicidas Industriais/administração & dosagem , Niacinamida/análogos & derivados , Resíduos de Praguicidas/análise , Óleos de Plantas/administração & dosagem , Pirimidinas/administração & dosagem , Compostos de Bifenilo/análise , Botrytis/efeitos dos fármacos , Fragaria/química , Fragaria/microbiologia , Fungicidas Industriais/análise , Niacinamida/administração & dosagem , Niacinamida/análise , Doenças das Plantas/prevenção & controle , Óleos de Plantas/análise , Pirimidinas/análiseRESUMO
Pyrethroids have been reported to interact synergistically when co-exposed with azoles fungicides in different organisms. In the present study, we investigated the mixture toxicity of fenvalerate (FEN) and triadimefon (TDF) toward embryos of Gobiocypris rarus after 96 h exposure. Results demonstrated that TDF enhanced the acute toxicity of FEN. Exposure to binary mixtures of FEN and TDF resulted in synergistic responses of endocrine disruption by inducing the transcripts of several genes including vtg, erα, erß1, erß2, cyp19a, cyp1a, cyp4, cyp11a, gnrh3, gnrhr1a, star, and dmrt1. Furthermore, FEN and TDF mixture increased the VTG level and aromatase activity in rare minnow embryos. FEN and TDF co-exposure also regulated the mRNA of vezf, hsp70, p53, gadd45α, induced the synthesis of ROS and activity of GST, suggesting the synergistic potential of oxidative stress induced by FEN and TDF co-exposure. The results indicated that binary mixtures of FEN and TDF could simultaneously induce endocrine disruption and oxidative stress in a synergistic manner during rare minnow embryo development.
Assuntos
Cyprinidae/crescimento & desenvolvimento , Desenvolvimento Embrionário/efeitos dos fármacos , Disruptores Endócrinos/toxicidade , Nitrilas/toxicidade , Piretrinas/toxicidade , Triazóis/toxicidade , Animais , Aromatase/genética , Aromatase/metabolismo , Cyprinidae/fisiologia , Sinergismo Farmacológico , Embrião não Mamífero/citologia , Embrião não Mamífero/efeitos dos fármacos , Embrião não Mamífero/metabolismo , Proteínas de Peixes/genética , Proteínas de Peixes/metabolismo , Regulação da Expressão Gênica/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo , Receptores de Estrogênio/genética , Receptores de Estrogênio/metabolismoRESUMO
Contaminants in the environment do not appear singly and usually occur as mixtures. We applied the combination index (CI)-isobologram method which allows computerized quantitation of synergism, additive effect and antagonism to determine the nature of toxicological interactions of two pesticides λ-cyhalothrin, imidacloprid, and heavy metal cadmium towards earthworm Eisenia fetida. In an artificial soil test, λ-cyhalothrin and Cd combination was slightly synergistic at low effect levels which turned into a slight antagonism above f(a) values of 0.6, while the binary mixtures containing imidacloprid exhibited antagonism. The presence of imidacloprid in the ternary mixture also resulted in an antagonistic effect to the earthworms. This behavior became more antagonistic in the ternary mixture in filter paper tests.
Assuntos
Cádmio/toxicidade , Imidazóis/toxicidade , Nitrilas/toxicidade , Nitrocompostos/toxicidade , Oligoquetos/efeitos dos fármacos , Piretrinas/toxicidade , Animais , Poluição Ambiental/análise , Neonicotinoides , Praguicidas/toxicidade , Solo/química , Poluentes do Solo/toxicidade , Testes de Toxicidade AgudaRESUMO
Mixtures of organophosphate (OP) and carbamate (CB) pesticides are commonly detected in freshwater ecosystems. These pesticides inhibit the activity of acetylcholinesterase (AChE) and have potential to interfere with behaviors that may be essential for the survival of species. Although the effects of individual anticholinesterase insecticides on aquatic species have been studied for decades, the neurotoxicity of mixtures is still poorly understood. In the present study, brain AChE inhibition in carp (Cyprinus carpio) exposed to a series of concentrations of the organophosphates (malathion and triazophos) as well as the carbamates (fenobucarb and carbosulfan) was measured. In equitoxic mixtures, the observed AChE activity inhibition of the malathion plus triazophos, and triazophos plus carbosulfan mixtures, was synergism. In equivalent concentration mixtures, the combination of malathion plus fenobucarb mixture conformed to synergism, while the observed AChE activity inhibition of the remaining pairings was less than additive. Single pesticide risk assessments are likely to underestimate the impacts of these insecticides on carps in aquatic environment where mixtures occur. Moreover, mixtures of pesticides that have been commonly reported in aquatic ecosystems may pose a more important challenge than previously anticipated.
Assuntos
Acetilcolinesterase/metabolismo , Carpas/metabolismo , Inseticidas/toxicidade , Animais , Encéfalo/efeitos dos fármacos , Encéfalo/enzimologia , Carbamatos/toxicidade , Inibidores da Colinesterase/toxicidade , Relação Dose-Resposta a Droga , Sinergismo Farmacológico , Malation/toxicidade , Organotiofosfatos/toxicidade , Triazóis/toxicidade , Poluentes Químicos da Água/toxicidadeRESUMO
The health risk to humans of pesticide application on minor crops, such as strawberry, requires quantification. Here, the dissipation and residual levels of three fungicides (pyraclostrobin, myclobutanil, and difenoconazole) were studied for strawberry under greenhouse conditions using high-performance liquid chromatography (HPLC)-tandem mass spectrometry after Quick, Easy, Cheap, Effective, Rugged, and Safe extraction. This method was validated using blank samples, with all mean recoveries of these three fungicides exceeding 80%. The residues of all three fungicides dissipated following first-order kinetics. The half-lives of pyraclostrobin, myclobutanil, and difenoconazole were 1.69, 3.30, and 3.65 days following one time application and 1.73, 5.78, and 6.30 days following two times applications, respectively. Fungicide residue was determined by comparing the estimated daily intake of the three fungicides against the acceptable daily intake. The results indicate that the potential health risk of the three fungicides was not significant in strawberry when following good agricultural practices (GAP) under greenhouse conditions.
Assuntos
Monitoramento Ambiental , Fragaria/química , Fungicidas Industriais/análise , Resíduos de Praguicidas/análise , Agricultura/métodos , Carbamatos , Cromatografia Líquida , Dioxolanos , Fungicidas Industriais/toxicidade , Meia-Vida , Espectrometria de Massas , Nitrilas , Resíduos de Praguicidas/toxicidade , Pirazóis , Medição de Risco , Estrobilurinas , TriazóisRESUMO
Carbendazim is one of the most widespread environmental contaminant that can cause major concern to human and animal reproductive system. To date, very few studies have been conducted on the toxic effect of carbendazim in the non-target organism zebrafish (Danio rerio). The study presented here aimed to assess how carbendazim triggers apoptosis, immunotoxicity and endocrine disruption pathways in zebrafish during its embryo development. Our results demonstrated that the expression patterns of many key genes involved in cell apoptosis pathway (e.g. P53, Mdm2, Bbc3 and Cas8) were significantly up-regulated upon the exposure to carbendazim at the concentration of 500 µg/L, while the Bcl2 and Cas3 were down-regulated at the same concentration, interestingly, the expression level of Ogg1 decreased at all the exposure concentrations. It was also observed that the mRNA levels of CXCL-C1C, CCL1, IL-1b and TNFα which were closely related to the innate immune system, were affected in newly hatched zebrafish after exposed to different concentrations of carbendazim. Moreover, the expression of genes that are involved in the hypothalamic-pituitary-gonadal/thyroid (HPG/HPT) axis including VTG, ERα, ERß2, Dio1, Dio2, Thraa and Thrb were all down-regulated significantly after the exposure to carbendazim. The expression levels of two cytochrome P450 aromatases CYP19a and CYP19b were increased significantly after 20 and 100 µg/L carbendazim exposure, respectively. Taken together, our results indicated that carbendazim had the potential to induce cell apoptosis and cause immune toxicity as well as endocrine disruption in zebrafish during the embryo developmental stage. The information presented here also help to elucidate the environmental risks caused by the carbendazim-induced toxicity in aquatic organisms.
Assuntos
Apoptose/efeitos dos fármacos , Benzimidazóis/farmacologia , Carbamatos/farmacologia , Disruptores Endócrinos/farmacologia , Regulação da Expressão Gênica no Desenvolvimento/efeitos dos fármacos , Imunidade Inata/efeitos dos fármacos , Imunotoxinas/farmacologia , Peixe-Zebra/genética , Análise de Variância , Animais , Apoptose/genética , Primers do DNA/genética , Eletroforese em Gel de Ágar , Regulação da Expressão Gênica no Desenvolvimento/imunologia , Hormônios Esteroides Gonadais/biossíntese , Hormônios Esteroides Gonadais/metabolismo , RNA Mensageiro/imunologia , RNA Mensageiro/metabolismo , Reação em Cadeia da Polimerase em Tempo Real , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Espectrofotometria Ultravioleta , Hormônios Tireóideos/biossíntese , Hormônios Tireóideos/metabolismo , Peixe-Zebra/embriologia , Peixe-Zebra/imunologiaRESUMO
Mixtures of organophosphate (OP) and carbamate (CB) insecticides are commonly detected in freshwater habitats. These insecticides inhibit the activity of acetylcholinesterase (AChE) and have potential to interfere with behaviors that may be essential for survival of species. Although the effects of individual anticholinesterase insecticides on aquatic species have been studied for decades, the combined toxicity of mixtures is still poorly understood. In the present study, we assessed whether pesticides in a mixture act in isolation (resulting in additive AChE inhibition) or whether components interact to produce either antagonistic or synergistic toxicity. Brain AChE inhibition in carp (Cyprinus carpio L.) exposed to a series of concentrations of the OP (chlorpyrifos, malathion and triazophos) as well as the CB (fenobucarb and carbosulfan) were measured. The concentration addition (CA) model and the isobole method were used to determine whether toxicological responses to binary mixtures of pesticides. In 50:50 % effect mixtures, the observed combined toxicity of chlorpyrifos and malathion was significantly higher than observed and was considered as synergistic. For equivalent dose mixtures, when chlorpyrifos mixed with fenobucarb or malathion, the observed toxicities were significantly higher than predicted, suggesting synergistic joint actions. The rest five binary combinations exhibited concentration additive or slight antagonistic joint actions. The CA model and the isobole method provided estimates of mixture toxicity that did not markedly underestimate the measured toxicity, therefore these methods are suitable to use in ecological risk assessments of pesticide mixtures.
Assuntos
Acetilcolinesterase/metabolismo , Carpas/metabolismo , Clorpirifos/toxicidade , Inseticidas/toxicidade , Testes de Toxicidade/métodos , Animais , Carbamatos/toxicidade , Inibidores da Colinesterase/toxicidade , Malation/toxicidade , Organotiofosfatos/toxicidade , Sinergistas de Praguicidas/toxicidade , Triazóis/toxicidadeRESUMO
Polylactic acid (PLA) is an eco-friendly material that can help address the problems of petroleum depletion and pollution. Blending renewable biomass materials with PLA to create composite foams with a tunable pore structure, superior performance, and low cost is a green technique for improving the pore structure and mechanical characteristics of single PLA foams. PLA/TP composites were created using melted tomato peel pomace powder (TP), which has a lamellar structure, as a reinforcing agent. Then, the relationship between the vesicle structure, morphology, and properties of the PLA/TP composite foams produced through supercritical CO2 intermittent foaming were investigated. The findings revealed that TP considerably enhanced the rheological characteristics and crystalline behavior of PLA. The PLA/TP composite foam had a better cell structure, compression characteristics, and wettability than pure PLA. The expansion ratio of the PLA/TP composite could reach 18.8, and its thermal conductivity decreased from 174.2 mW/m·K at 100 °C to 57.8 mW/m·K at 120 °C. Furthermore, annealing before foaming decreased the average composite foam blister size from 110.09 to 66.53 µm, and the annealing process also improved compression performance. This study contributes to solving environmental difficulties and creating PLA foams with controlled bubble structures, uniform bubble sizes, and outstanding overall performance.
Assuntos
Dióxido de Carbono , Poliésteres , Pós , Solanum lycopersicum , Poliésteres/química , Dióxido de Carbono/química , Solanum lycopersicum/química , Reologia , MolhabilidadeRESUMO
The influence of short-range interactions between a multi-phase, multi-component mixture and a solid wall in confined geometries is crucial in life sciences and engineering. In this work, we extend the Cahn-Hilliard model with dynamic boundary conditions from a binary to a ternary mixture, employing the Onsager principle, which accounts for the cross-coupling between forces and fluxes in both the bulk and surface. Moreover, we have developed a linear, second-order and unconditionally energy-stable numerical scheme for solving the governing equations by utilizing the invariant energy quadratization method. This efficient solver allows us to explore the impacts of wall-mixture interactions and dynamic boundary conditions on phenomena like spontaneous phase separation, coarsening processes and the wettability of droplets on surfaces. We observe that wall-mixture interactions influence not only surface phenomena, such as droplet contact angles, but also patterns deep within the bulk. Additionally, the relaxation rates control the droplet spreading on surfaces. Furthermore, the cross-coupling relaxation rates in the bulk significantly affect coarsening patterns. Our work establishes a comprehensive framework for studying multi-component mixtures in confined geometries.