RESUMO
BACKGROUND: Anti-PD-1/PD-L1 treatment has achieved durable responses in TNBC patients, whereas a fraction of them showed non-sensitivity to the treatment and the mechanism is still unclear. METHODS: Pre- and post-treatment plasma samples from triple negative breast cancer (TNBC) patients treated with immunotherapy were measured by tandem mass tag (TMT) mass spectrometry. Public proteome data of lung cancer and melanoma treated with immunotherapy were employed to validate the findings. Blood and tissue single-cell RNA sequencing (scRNA-seq) data of TNBC patients treated with or without immunotherapy were analyzed to identify the derivations of plasma proteins. RNA-seq data from IMvigor210 and other cancer types were used to validate plasma proteins in predicting response to immunotherapy. RESULTS: A random forest model constructed by FAP, LRG1, LBP and COMP could well predict the response to immunotherapy. The activation of complement cascade was observed in responders, whereas FAP and COMP showed a higher abundance in non-responders and negative correlated with the activation of complements. scRNA-seq and bulk RNA-seq analysis suggested that FAP, COMP and complements were derived from fibroblasts of tumor tissues. CONCLUSIONS: We constructe an effective plasma proteomic model in predicting response to immunotherapy, and find that FAP+ and COMP+ fibroblasts are potential targets for reversing immunotherapy resistance.
Assuntos
Imunoterapia , Proteômica , Análise de Célula Única , Neoplasias de Mama Triplo Negativas , Humanos , Neoplasias de Mama Triplo Negativas/tratamento farmacológico , Neoplasias de Mama Triplo Negativas/sangue , Neoplasias de Mama Triplo Negativas/terapia , Neoplasias de Mama Triplo Negativas/genética , Neoplasias de Mama Triplo Negativas/imunologia , Feminino , Imunoterapia/métodos , Análise de Célula Única/métodos , Proteômica/métodos , Antígeno B7-H1/sangue , Biomarcadores Tumorais/sangue , Biomarcadores Tumorais/genética , Transcriptoma , Inibidores de Checkpoint Imunológico/uso terapêutico , Perfilação da Expressão Gênica , ProteomaRESUMO
The exploration of the physical attributes of the recently discovered orthocarbonate Sr3CO5 is significant for comprehending the carbon cycle and storage mechanisms within the Earth's interior. In this study, first-principles calculations are initially used to examine the structural phase transitions of Sr3CO5 polymorphs within the range of lower mantle pressures. The results suggest that Sr3CO5 with the Cmcm phase exhibits a minimal enthalpy between 8.3 and 30.3 GPa. As the pressure exceeds 30.3 GPa, the Cmcm phase undergoes a transition to the I4/mcm phase, while the experimentally observed Pnma phase remains metastable under our studied pressure. Furthermore, the structural data of SrO, SrCO3, and Sr3CO5 polymorphs are utilized to develop a deep learning potential model suitable for the Sr-C-O system, and the pressure-volume relationship and elastic constants calculated using the potential model are in line with the available results. Subsequently, the elastic properties of Cmcm and I4/mcm phases in Sr3CO5 at high temperature and pressure are calculated using the molecular dynamics method. The results indicate that the I4/mcm phase exhibits higher temperature sensitivity in terms of elastic moduli and wave velocities compared to the Cmcm phase. Finally, the thermodynamic properties of the Cmcm and I4/mcm phases are predicted in the range of 0-2000 K and 10-120 GPa, revealing that the heat capacity and bulk thermal expansion coefficient of both phases increase with temperature, with the constant volume heat capacity gradually approaching the Dulong-Petit limit as the temperature rises.
RESUMO
Pseudomonas fluorescens is a spoilage bacterium in food that has the ability to maintain growth and reproduction in high-salt environments. It acts as a defence mechanism through the exclusion of ions and the formation of biofilms. Hence, disrupting this defence mechanism may be a good way to control food spoilage. In this study, a specific flavonoid small molecule baicalin was found, which was able to dismantle the defence mechanism of the bacteria at a lower concentration (400 µM) of treatment. In synergy with salt, baicalin showed a significant inhibitory effect on the growth, c-di-gmp synthetics and biofilm formation of Pseudomonas fluorescens Pf08. Through transcriptomics, we also found that baicalein interfered with bacterial transport and polysaccharide production functions. Through molecular docking and QPCR, we found that baicalin is able to binding with the RpoS protein through hydrogen bonding and thus interfere with its function.
Assuntos
Pseudomonas fluorescens , Simulação de Acoplamento Molecular , BiofilmesRESUMO
To study the contamination levels of perfluoroalkyl acids (PFAAs) in Chinese eggs and the effects of persistent organic pollutant (POP) amendments to the Stockholm Convention blacklist, 3200 eggs from 10 major producing areas were collected from June 2013 to May 2017. Seventeen PFAAs in eggs were analysed. Perfluorooctane sulphonic acid (PFOS), perfluoropentanoic acid (PFPeA) and perfluorooctanoic acid (PFOA) were the main PFAAs in eggs. Perfluoroalkyl carboxylic acids (PFCAs) and short-chain PFAAs levels in eggs decreased after the amendment was implemented in China (p < .05), but no significant difference was observed in PFOS. The average ΣPFAAs of eggs from 10 major producing areas was 0.23 ng/g (Assuntos
Fluorocarbonos
, Poluentes Químicos da Água
, China
, Monitoramento Ambiental
, Fluorocarbonos/análise
, Contaminação de Alimentos/análise
, Rios
, Poluentes Químicos da Água/análise
RESUMO
In the present study, ultrasound-assisted extraction was employed to extract the general flavone from celery leaves using response surface methodology and BP neural network model with a genetic algorithm (GA). The effects of temperature, time, solid-liquid ratio, and ethanol concentration on the extraction results were assessed by Box-Behnken design. Further optimization of the process was performed by GA-BP. Our results showed that the optimal conditions were an ethanol concentration of 70.31%, a temperature of 67.2 °C and an extraction time of 26.6 min. In addition, significant antioxidant activity and in vitro bacteriostasis were observed. We found that the total flavonoids of the celery leaves exerted a strong inhibitory effect on Escherichia coli, Staphylococcus aureus, and Bacillus subtilis. Additionally, considerable DPPH· and ·OH scavenging effects were exerted by flavonoids. Therefore, flavonoids from celery leaves can be considered natural antioxidants and bacterial inhibitors.
Assuntos
Apium , Flavonoides , Extratos Vegetais , Folhas de Planta , Algoritmos , Apium/química , Bacillus subtilis/efeitos dos fármacos , Escherichia coli/efeitos dos fármacos , Etanol/química , Flavonoides/isolamento & purificação , Flavonoides/farmacologia , Redes Neurais de Computação , Extratos Vegetais/farmacologia , Folhas de Planta/química , Staphylococcus aureus/efeitos dos fármacos , Temperatura , Fatores de TempoRESUMO
Attention can be involuntarily attracted by a distractor that matches the current attentional control settings (ACSs). However, it remains unclear whether two category-specific ACSs can operate independently. By defining a target as a combination of two prototype-based categories, the present event-related potential (ERP) study investigated how color-category and shape-category ACSs operate within a search task paradigm and the effects of temporal task demands on these ACSs. The matching level between target and distractor was manipulated to separate the effects of each ACS. The relative position between target and distractor was employed to isolate the attentional processing of the distractor from the target. Furthermore, two display durations were used to manipulate the temporal task demands, including a short fixed window (800 ms) and a dynamic window extended until the user responded. Our results support a two-stage selection scenario. In early stage, the color- and shape-ACS independently guided attention to task-relevant property (N2pc components) and suppressed attention toward task-irrelevant properties (PD components). In late stage, these two independent ACSs were integrated into a holistic ACS to interfere with the consolidation (contralateral delay activity components) and behavioral performance (accuracy and RTs) of target identification. Moreover, an early N1/P1 component might reflect a preattentive enhancement of relevant information or a preattentive suppression of irrelevant objects. These two category-specific ACSs weights differently in varied temporal task demands. These findings support the idea that independent early processing is followed by integrated late processing, which can be applied to category-based attentional capture with different temporal task demands.
Assuntos
Atenção/fisiologia , Córtex Cerebral/fisiologia , Percepção de Cores/fisiologia , Potenciais Evocados/fisiologia , Neuroimagem Funcional , Desempenho Psicomotor/fisiologia , Percepção Espacial/fisiologia , Adolescente , Adulto , Eletroencefalografia , Potenciais Evocados Visuais/fisiologia , Feminino , Humanos , Masculino , Fatores de Tempo , Adulto JovemRESUMO
B-cell non-Hodgkin's lymphoma (B-NHL) is a lymphoproliferative disorder that affects B lymphocytes. Chimeric antigen receptor (CAR) T-cell immunotherapy is a new type of immunotherapy that uses genetic engineering techniques to modify and expand the patient's autoimmune cells in vitro, after which these cells are reinfused into the patient. CAR-T cell immunotherapy has the potential to treat different types of B-cell lymphoma. Many clinical studies have shown that CAR-T cell therapy has significant antitumor effects on B-cell lymphoma. Although much work has been carried out to improve the efficacy of CAR-T cell therapy and to reduce associated side effects, there are still many issues to address. CAR-T cell therapy shows significant promise in treating B-NHL, but some patients still have a poor initial response to this therapy where the infused CAR-T cells show insufficient persistence. With the rapid development of immunological therapy, combination therapy has been certified to improve the efficacy of CAR-T cell therapy. Targeted drugs such as programmed death-1 (PD-1) inhibitors, programmed cell death-ligand 1 (PD-L1) inhibitors, and Bruton's tyrosine kinase (BTK) inhibitors may further enhance the efficacy and reduce the side effects of CAR-T cell treatment. This article reviews the rationale and relevant clinical research on combination therapy based on CAR-T cell therapy for B-cell lymphoma treatment.
RESUMO
This study investigated the levels, spatial distribution, sources, and ecological risks of 16 perfluorinated compounds (PFCs) in 68 surface soil samples (0-20 cm) from 7 cities in the Pearl River Delta (PRD), China. Sixteen target PFCs, including perfluoroalkyl carboxylic acids (PFCAs, C5-C14, C16, and C18) and perfluoroalkyl sulfonic acids (PFSAs, C4, C6, C8, and C10), were analyzed by high-performance liquid chromatography-negative electrospray ionization-tandem mass spectrometry (HPLC/ESI-MS/MS). Concentrations of total PFCs (∑PFCs) ranged from 2.19 to 98.5 µg kg-1 (dry weight, dw), with an average of 5.97 µg kg-1 dw. Perfluorooctane sulfonate (PFOS) was the dominant PFC, accounting for 23.9% of ∑PFCs. The highest ∑PFCs was found in the soil sample collected from Dongguan with a large number of manufacturing industries. There were no significant differences of ∑PFCs among unban, industrial, and agricultural soils, indicating similar pollution sources in soil of the PRD. More than 70% of ∑PFCs in soil of the PRD could be attributed to the four principal components, represented by PFOS and perfluorooctanoic acid (PFOA), perfluoropentanoic acid (PFPeA) and perfluorohexanoic acid (PFHxA), perfluorodecanoic acid (PFDA), and perfluoroundecanoic acid (PFUdA). Ecological risk assessment indicated that PFOA had low risk to soil plants and animals. However, the risk of PFOS to soil plants was relatively high in some studied regions.
Assuntos
Poluentes do Solo/análise , Ácidos Alcanossulfônicos/análise , Caproatos/análise , Caprilatos/análise , China , Cidades , Ácidos Decanoicos/análise , Monitoramento Ambiental/métodos , Ácidos Graxos/análise , Fluorocarbonos/análise , Espectrometria de Massas por Ionização por Electrospray , Espectrometria de Massas em TandemRESUMO
Perfluorinated compounds (PFCs) are of special concern due to their environmental persistence and biotoxicity. In the present study, spatial distribution of PFCs in atmosphere of the Pearl River Delta (PRD) of Southern China was investigated from November 2013 to January 2014. Forty-two air samples were collected using passive air samplers to determine the 13 target analytes, including perfluoroalkyl carboxylic acids (PFCAs, C5-14) and perfluoroalkyl sulfonic acids (PFSAs, C4, C6, and C8). Results showed that the total concentrations of PFCs (ΣPFCs) ranged from 53.7 to 225 pg m-3 with an average level of 122 ± 41.5 pg m-3, indicating a wide variation on ΣPFCs in atmosphere of the PRD. Perfluorooctane sulfonate (PFOS) was the most abundant PFCs, followed by perfluorooctanoic acid (PFOA), perfluoropentanoic acid (PFPeA), and perfluoroheptanoic acid (PFHpA). PFOS, PFOA, PFPeA, and PFHpA accounted for 26%, 22%, 21%, and 19% of ΣPFCs, respectively. A general decline in ΣPFCs was observed in the atmosphere from south PRD to north PRD. It was likely related to the industrial distribution, population density, and wind direction. In addition, the same order of magnitude of PFOS and lower level of PFOA were observed in this study compared with those in atmosphere sampled in other regions. The lifetime risk indexes on the PFOS and PFOA concentrations were much less than unity, suggesting a lower nononcogenic risk to residents in the PRD.
Assuntos
Poluentes Atmosféricos/análise , Fluorocarbonos/análise , Ácidos Alcanossulfônicos/análise , Caprilatos/análise , China , Monitoramento Ambiental/métodos , Ácidos Heptanoicos/análise , Humanos , Medição de RiscoRESUMO
Dental pulp inflammation is a common bacterially driven inflammation characterized by the local accumulation of inflammatory mediators in human dental pulp. DNA methylation is a crucial epigenetic modification that that plays a fundamental role in gene transcription, and its role in inflammation-related diseases has recently attracted attention. However, its role in dental pulp inflammation is poorly understood. This study is aimed to elucidate the role of DNA methylation in lipopolysaccharide (LPS)-induced inflammatory reaction in human dental pulp cells (hDPCs). hDPCs were pretreated with DNA methylation inhibitor 5-aza-2'-deoxycytidine (5-Aza-CdR) and a cytokine antibody array was used to detect LPS-induced cytokine expression. The results indicated that 5-Aza-CdR significantly increased the expression of several pro-inflammatory cytokines in LPS-treated cells, including IL-6, IL-8, GM-CSF, MCP-2 and RANTES. The increased expression levels of IL-6 and IL-8 were further verified by qRT-PCR and ELISA. Furthermore, pretreatment with 5-Aza-CdR resulted in upregulation of p-IKKα/ß, p-IκBα, p-p65 and p-ERK in the NK-κB and MAPK pathways. In addition, the 5mC level of the TRAF6 promoter was significantly decreased following 5-Aza-CdR pretreatment in the LPS-stimulated hDPCs. The findings indicate that 5-Aza-CdR significantly enhances the expression of proinflammatory cytokines and activates the NF-κB and MAPK signaling pathways by eliciting a decline in the 5mc level in the TRAF6 promoter in hDPCs, suggesting that DNA methylation may play an important role in dental pulp inflammation. This study highlights the important role of DNA methylation in the immunity defense of dental pulp infection.
Assuntos
Decitabina/farmacologia , Polpa Dentária/citologia , Inflamação/induzido quimicamente , Inflamação/metabolismo , Lipopolissacarídeos/farmacologia , Fator 6 Associado a Receptor de TNF/metabolismo , Células Cultivadas , Citocinas/metabolismo , Metilação de DNA/efeitos dos fármacos , Metilação de DNA/genética , Humanos , Interleucina-6/metabolismo , Interleucina-8/metabolismo , Regiões Promotoras Genéticas/efeitos dos fármacos , Regiões Promotoras Genéticas/genética , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/genética , Fator 6 Associado a Receptor de TNF/genéticaRESUMO
To study the perfluoroalkyl acid (PFAAs) contamination in seven major drainage basins of China and the exposure risk to resident populations via drinking water sourced from these basins, a risk assessment model of the US EPA and a scenario-based risk assessment method were applied to analyze the PFAA pollution characteristics and to evaluate the average daily dose and health risk to adults, adolescents, and children. In the intermediate-exposure scenario, results showed that the ∑PFAAs median for the seven major drainage basins was 14 ng·L-1, with perfluorooctanoic acid (PFOA), perfluorobutanoic acid (PFBA), and perfluorooctane sulfonic acid (PFOS) the main contaminants, and that the contamination levels were the highest in the Songliao River and Taihu Lake basins. In the high-exposure scenario, the discharge proportion of perfluoroalkyl carboxylic acids with ≤ 6 carbon chains among the ∑PFAAs was higher than that in the intermediate-exposure scenario. In addition, certain sections tended to be more polluted than others in the Yellow River and Yangtze River basins. Risk assessment showed that PFOA and PFOS exposure via drinking water posed no health risk to Chinese residents, and that the average daily ingestion of drinking water of Chinese adolescents was below the suggested amount.
Assuntos
Água Potável/análise , Fluorocarbonos/análise , Poluentes Químicos da Água/análise , Adolescente , Adulto , Ácidos Alcanossulfônicos , Caprilatos , Criança , China , Monitoramento Ambiental , Humanos , Medição de Risco , RiosRESUMO
Dental pulp inflammation is a bacterially driven inflammation process characterized by the local accumulation of cytokines/chemokines that participate in destructive processes in the pulp. Multiple mechanisms are involved in dental pulp inflammation, including epigenetic events, such as DNA methylation/demethylation. Ten-eleven translocation 2 (TET2) is a recently discovered DNA methylcytosine dioxygenase that plays important roles in inflammatory disease. However, its role in the inflammatory response of dental pulp is unknown. We observed elevated mRNA and protein levels of TET2 after lipopolysaccharide (LPS) stimulation in human dental pulp cells (hDPCs). To identify the effects of TET2 on cytokine expression, TET2 was knocked down and cytokines were detected using a cytokine antibody array after LPS stimulation. The protein expression of GM-CSF, IL-6, IL-8 and RANTES decreased in the LPS-induced hDPCs following TET2 knockdown. The downregulated expression levels of IL-6 and IL-8 were further confirmed by real-time quantitative polymerase chain reaction (qRT-PCR) and enzyme-linked immunosorbent assay (ELISA). Additionally, the phosphorylation levels of IKK-α/ß, p65 and IκBα of the NF-κB signaling pathway were decreased in the TET2-silenced group. Furthermore, the global 5-hydroxymethylcytosine (5hmC) level was significantly decreased and the genomic 5-methylcytosine (5mC) level was increased in the TET2-deficient hDPCs; TET2 depletion resulted in a decrease in the 5hmC level of the MyD88 promoter following LPS stimulation. These findings indicate that TET2 knockdown inhibits LPS-induced inflammatory response in hDPCs by downregulating MyD88 hydroxymethylation. Thus, TET2-dependent DNA demethylation might play an important role in dental pulp inflammation as an epigenetic regulator.
Assuntos
Citocinas/metabolismo , Proteínas de Ligação a DNA/metabolismo , Polpa Dentária/metabolismo , Dioxigenases/metabolismo , Inflamação/metabolismo , Fator 88 de Diferenciação Mieloide/metabolismo , Proteínas Proto-Oncogênicas/metabolismo , Citocinas/efeitos dos fármacos , Metilação de DNA/genética , Proteínas de Ligação a DNA/genética , Polpa Dentária/citologia , Polpa Dentária/efeitos dos fármacos , Polpa Dentária/imunologia , Dioxigenases/genética , Epigênese Genética/genética , Técnicas de Silenciamento de Genes , Humanos , Inflamação/imunologia , Lipopolissacarídeos/farmacologia , Fator 88 de Diferenciação Mieloide/genética , Cultura Primária de Células , Proteínas Proto-Oncogênicas/genética , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , RNA Interferente Pequeno/genética , RNA Interferente Pequeno/metabolismoRESUMO
To study the contamination of perfluoroalkyl acids (PFAAs) in Chinese food and the risk of dietary exposure for the Chinese population, the data of 17 PFAAs covering 38 cities throughout China in 15 groups of foods were collected for meta-analysis from published and available research literature. Using food consumption and body weight parameters, estimated dietary intakes (EDIs) were calculated for evaluation using the Scenario-Based Risk Assessment (SceBRA) modelling. Among food groups, the highest ΣPFAAs concentrations and EDI contributions were both found in poultry (363 ng/g), fish and shrimp (313 ng/g), dark vegetables (309 ng/g), fruits (116 ng/g) and pork (25 ng/g). The EDI of adults in the high-exposure scenario was about twice that of the intermediate-exposure scenario, while the EDI of children was about twice that of adults' EDI in the intermediate-exposure scenario. In addition, the PFOS EDI for children under high exposure approached its tolerable daily intake (TDI). Therefore high dietary exposure to PFAAs is giving rise to an increased health risk, especially for children.
Assuntos
Exposição Ambiental/análise , Poluentes Ambientais/análise , Fluorocarbonos/análise , Contaminação de Alimentos/análise , China , Ingestão de Alimentos , Humanos , Medição de RiscoRESUMO
In order to explore the pollution characteristics of perfluorinated compounds (PFCs), 10 surface seawaters and 7 surface sediments were collected in offshore marine area of Shenzhen (offshore distance >2 km) in September 2013. All the samples were prepared by solid-phase extraction and analyzed using high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/ MS). The results showed that 10 PFCs, including C4, C6 and C8 perfluorinated sulfonates (PFSAs) and C5-C11, perfluorinated carboxylic acids (PFCAs) were detected in the surface waters. ∑ PFC concentrations ranged from 1.74 ng x L(-1) to 14.7 ng x L(-1) with PFBS, PFOS and PFOA being the dominant compounds. The spatial distribution of ∑ PFC concentrations displayed the characteristic of "the west being higher than the east", with ∑ PFC concentrations of Lingding Sea and Shenzhen Bay being higher than those of Daya Bay and Dapeng Bay (P < 0.05). The farther the sampling location was from the shore, the lower the ∑ PFC concentrations were. Direct sewage emissions and rivers emptying into the sea might be the primary sources of PFCs in the surface seawaters. 8 PFCs, including C6 and C8 PFSAs and C5, C6, and C8-C11 PFCAs were detected in the surface sediments. ∑ PFC concentrations ranged from 2.22 micorg x kg(-1) to 2.62 microg x kg(-1) with PFOS being the dominant compounds. There was a small change of ∑ PFC concentrations in surface sediments, which might be contributed by the adsorption from overlying water. The adsorption of PFCs on sediment significantly increased with the increasing length of carbon chain, and the adsorption of PFSA was higher than that of PFCA with the same length of carbon chain as PFSA. Additionally, the comparison with other seawater PFC measurements showed high PFBS pollution in this study, whereas the level of PFOS in sediment was close to those of other studies.
Assuntos
Fluorocarbonos/análise , Água do Mar/química , Poluentes Químicos da Água/análise , Ácidos Carboxílicos , Monitoramento Ambiental , Sedimentos Geológicos/química , Rios , Extração em Fase SólidaRESUMO
This study investigated the occurrence of perfluorinated compounds (PFCs) in the atmosphere of Shenzhen, China. 11 PFCs, including two perfluoroalkyl sulfonic acids (PFSAs, C6 and C8) and perfluoroalkyl carboxylic acids (PFCAs, C4-12) were determined by high performance liquid chromatography-negative electrospray ionization-tandem mass spectrometry (HPLC/ESI-MS/MS). Total PFC concentrations (∑ PFCs) in the atmospheric samples ranged from 3.4 to 34 pg m(-3) with an average of 15 pg m(-3). Perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) were the two most abundant PFCs and on average accounted for 35% and 22% of ∑ PFCs, respectively. ∑ PFCs and total PFCA concentrations (∑ PFCAs) showed a tendency of low-lying East West, while the distribution of total PFSA concentrations (∑ PFSAs) was uniform. Higher concentrations of ∑ PFCs were found in Bao'an District which had very well-developed manufacturing industries. PCA model was employed to quantitatively calculate the contributions of sources. The results showed that PFOA-factor, long chain PFCs-factor and PFOS-factor were the three main source categories for PFCs in the atmosphere. Meanwhile, long-distance transport of pollutants from southeastern coastal areas might be another source of PFCs in Shenzhen atmosphere. PFCs in the atmosphere were more positively correlated with the levels PM10 than PM2.5, which indicated PFCs were more likely to adhere to particles with relatively large sizes. The hazard ratios of noncancer risk through breathing based on PFOS and PFOA concentrations were calculated and were less than unity, suggesting that PFCs concentrations may pose no or immediate threat to the residents in Shenzhen.
Assuntos
Poluentes Atmosféricos/análise , Atmosfera/química , Monitoramento Ambiental , Fluorocarbonos/análise , Saúde , Análise Espacial , China , Cromatografia Líquida de Alta Pressão , Humanos , Medição de Risco , Espectrometria de Massas em TandemRESUMO
This study investigated the occurrence of perfluoroalkyl acids (PFAAs) in surface water from 67 sampling sites along rivers of the Pearl River Delta in southern China. Sixteen PFAAs, including perfluoroalkyl carboxylic acids (PFCAs, C5-14, C16 and C18) and perfluoroalkyl sulfonic acids (PFSAs, C4, C6, C8 and C10) were determined by high performance liquid chromatography-negative electrospray ionization-tandem mass spectrometry (HPLC/ESI-MS/MS). Total PFAA concentrations (∑ PFAAs) in the surface water ranged from 1.53 to 33.5 ng·L(-1) with an average of 7.58 ng·L(-1). Perfluorobutane sulfonic acid (PFBS), perfluorooctanoic acid (PFOA), and perfluorooctane sulfonic acid (PFOS) were the three most abundant PFAAs and on average accounted for 28%, 16% and 10% of ∑ PFAAs, respectively. Higher concentrations of ∑ PFAAs were found in the samples collected from Jiangmen section of Xijiang River, Dongguan section of Dongjiang River and the Pearl River flowing the cities which had very well-developed manufacturing industries. PCA model was employed to quantitatively calculate the contributions of extracted sources. Factor 1 (72.48% of the total variance) had high loading for perfluorohexanoic acid (PFHxA), perfluoropentanoic acid (PFPeA), PFBS and PFOS. For factor 2 (10.93% of the total variance), perfluorononanoic acid (PFNA) and perfluoroundecanoic acid (PFUdA) got high loading. The sorption of PFCAs on suspended particulate matter (SPM) increased by approximately 0.1 log units for each additional CF2 moiety and that on sediment was approximately 0.8 log units lower than the SPM logKd values. In addition, the differences in the partition coefficients were influenced by the structure discrepancy of absorbents and influx of fresh river water. These data are essential for modeling the transport and environmental fate of PFAAs.
Assuntos
Monitoramento Ambiental , Fluorocarbonos/análise , Poluentes Químicos da Água/análise , Ácidos Alcanossulfônicos/análise , Caproatos/análise , Caprilatos/análise , China , Rios/químicaRESUMO
In order to study the concentrations of 14 perfluorinated compounds (PFCs) in 25 surface water samples collected from 12 Shenzhen reservoirs in November of 2012 and January of 2013, high performance liquid chromatography-tandem mass spectrometry was combined with solid phase extraction enrichment in this research. The results indicated that perfluorohexane sulfonate and long-chain (C > or = 11) PFCs were below the detection limit in all samples and perfluorooctane acid was the primary species. No significant difference in concentration was found between samples from the center of the reservoir and the outlet. Heavy precipitations diluted PFCs concentrations in surface water, but also led to PFOA input. PFCs concentrations in surface water of the reservoir were mainly affected by water inlet, source environment and geography. Although the water temperature had positive correlations with sigma PFCs concentration, the influence of heavy precipitations was stronger than that of water temperature.
Assuntos
Monitoramento Ambiental , Fluorocarbonos/análise , Água Doce/química , Ácidos Sulfônicos/análise , Poluentes Químicos da Água/análise , China , Cromatografia Líquida de Alta Pressão , Extração em Fase Sólida , Espectrometria de Massas em TandemRESUMO
To study the perfluorinated compounds (PFCs) residues through water treatments including flocculation, sedimentation, sand filtration, ozonation with activated carbon and chlorination, as well as the seasonal variation of PFCs in the raw water of waterworks, 13 PFCs species in the dissolved phase of raw water, finished water, as well as the water samples after flocculation, sedimentation, sand filtration, and ozonation with activated carbon filtration were measured by the high performance liquid chromatography-tandem mass spectrometry combined with solid phase extraction. Results indicated that sigma PFCs residue in water was higher in spring and summer than that in fall and winter. The vast majority of PFCs in samples were of short and medium chains (C < or = 10), and perfluorooctane sulfonate was the most typical residue species. Among the five water treatment stages, sedimentation, sand filtration and ozonation with activated carbon filtration can remove PFCs, while flocculation and chlorination significantly raise the levels of short- (C < or = 6) and medium-chain (10 > or = C > or = 7) PFCs, respectively, causing sigma PFCs increase in finished water by 10%-44% compared to raw water. However, the PFCs residues in finished water are still far below their limit values, posing no threat against human health.
Assuntos
Ácidos Alcanossulfônicos/química , Água Potável/química , Fluorocarbonos/química , Poluentes Químicos da Água/química , Purificação da Água/métodos , Cromatografia Líquida de Alta Pressão , Estações do Ano , Extração em Fase Sólida , Espectrometria de Massas em TandemRESUMO
Strain Hhs.015(T) (Saccharothrix yanglingensis sp. nov.), an antagonistic endophytic Saccharothrix actinomycete isolated from roots of cucumber plants, exhibited a broad antimicrobial spectrum in vitro and was active as a biocontrol against plant diseases in field trials. The SSY medium was used for production of antimicrobial metabolites by strain Hhs.015(T). However, this medium is too expensive for large-scale production. In this study, an alternative culture medium, based on agricultural waste products (e.g., apple pomace), was optimized. The results showed that the alternative medium contained 15 g apple pomace, 4 g rapeseed meal, 0.1 g KH(2)PO(4), and 0.6 g MgSO(4).7H(2)O in 1 L distilled water. This medium reduced the material costs by 91.5% compared to SSY medium. Response surface methodology (RSM) was used to investigate the influence of environmental variables on production of compounds of antimicrobial metabolites. The optimal conditions achieved were initial pH 7.0, medium volume of 90 mL in 250 mL flasks, rotary speed of 100 rpm, temperature 25 degrees C, and inoculation volume of 15.8%. The antimicrobial activity was increased by 20% by optimizing the environmental parameters. The results obtained allow an efficient production of components with antimicrobial activity by strain Hhs.015(T) on a large scale at low costs.