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1.
J Agric Food Chem ; 72(21): 11885-11899, 2024 May 29.
Artigo em Inglês | MEDLINE | ID: mdl-38747409

RESUMO

Actin, a multifunctional protein highly expressed in eukaryotes, is widely distributed throughout cells and serves as a crucial component of the cytoskeleton. Its presence is integral to maintaining cell morphology and participating in various biological processes. As an irreplaceable component of myofibrillar proteins, actin, including G-actin and F-actin, is highly related to food quality. Up to now, purification of actin at a moderate level remains to be overcome. In this paper, we have reviewed the structures and functions of actin, the methods to obtain actin, and the relationships between actin and food texture, color, and flavor. Moreover, actin finds applications in diverse fields such as food safety, bioengineering, and nanomaterials. Developing an actin preparation method at the industrial level will help promote its further applications in food science, nutrition, and safety.


Assuntos
Actinas , Qualidade dos Alimentos , Actinas/metabolismo , Actinas/química , Animais , Humanos
2.
JMIR Infodemiology ; 4: e49756, 2024 01 23.
Artigo em Inglês | MEDLINE | ID: mdl-38261367

RESUMO

BACKGROUND: Health agencies have been widely adopting social media to disseminate important information, educate the public on emerging health issues, and understand public opinions. The Centers for Disease Control and Prevention (CDC) widely used social media platforms during the COVID-19 pandemic to communicate with the public and mitigate the disease in the United States. It is crucial to understand the relationships between the CDC's social media communications and the actual epidemic metrics to improve public health agencies' communication strategies during health emergencies. OBJECTIVE: This study aimed to identify key topics in tweets posted by the CDC during the pandemic, investigate the temporal dynamics between these key topics and the actual COVID-19 epidemic measures, and make recommendations for the CDC's digital health communication strategies for future health emergencies. METHODS: Two types of data were collected: (1) a total of 17,524 COVID-19-related English tweets posted by the CDC between December 7, 2019, and January 15, 2022, and (2) COVID-19 epidemic measures in the United States from the public GitHub repository of Johns Hopkins University from January 2020 to July 2022. Latent Dirichlet allocation topic modeling was applied to identify key topics from all COVID-19-related tweets posted by the CDC, and the final topics were determined by domain experts. Various multivariate time series analysis techniques were applied between each of the identified key topics and actual COVID-19 epidemic measures to quantify the dynamic associations between these 2 types of time series data. RESULTS: Four major topics from the CDC's COVID-19 tweets were identified: (1) information on the prevention of health outcomes of COVID-19; (2) pediatric intervention and family safety; (3) updates of the epidemic situation of COVID-19; and (4) research and community engagement to curb COVID-19. Multivariate analyses showed that there were significant variabilities of progression between the CDC's topics and the actual COVID-19 epidemic measures. Some CDC topics showed substantial associations with the COVID-19 measures over different time spans throughout the pandemic, expressing similar temporal dynamics between these 2 types of time series data. CONCLUSIONS: Our study is the first to comprehensively investigate the dynamic associations between topics discussed by the CDC on Twitter and the COVID-19 epidemic measures in the United States. We identified 4 major topic themes via topic modeling and explored how each of these topics was associated with each major epidemic measure by performing various multivariate time series analyses. We recommend that it is critical for public health agencies, such as the CDC, to update and disseminate timely and accurate information to the public and align major topics with key epidemic measures over time. We suggest that social media can help public health agencies to inform the public on health emergencies and to mitigate them effectively.


Assuntos
COVID-19 , Comunicação em Saúde , Mídias Sociais , Humanos , Centers for Disease Control and Prevention, U.S. , COVID-19/epidemiologia , Emergências , Infodemiologia , Pandemias/prevenção & controle , Estados Unidos/epidemiologia
3.
J Sci Food Agric ; 104(3): 1564-1571, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-37807842

RESUMO

BACKGROUND: Myofibrillar proteins, the main contributors to the quality of meat products, are the main structural protein component of muscle and have functional properties such as the formation of a 3D protein gel network and water binding. The susceptibility of meat-derived proteins to heat-induced aggregation is the functional constraint that hinders their applications in industry, and so establishing an effective but simple method to improve their thermostability of the proteins is of great importance. RESULTS: In the present study, we describe an easy approach to perform high colloidal thermostability of both paramyosin and actin by mixing them at low ionic strength. The improvement in thermal stability was found to be derived from intermolecular interactions between these two different proteins through non-covalent binding with each other. Consequently, such interactions protected each of them from thermal-induced degradation compared to individual components. Notably, this binary native protein mixture rather than single paramyosin or actin component has the ability to form protein hydrogels with a shear-thinning and reversible sol-gel transformation behavior, which is markedly different from most of reported heat-induced, denatured protein hydrogels. CONCLUSION: The present study not only presents a facile and effective strategy for improvement of the thermal stability and gel properties of a binary paramyosin and actin mixture, but also enhances our understanding of how mutual interactions of protein components affect their physicochemical and functional properties. © 2023 Society of Chemical Industry.


Assuntos
Actinas , Tropomiosina , Tropomiosina/química , Actinas/química , Músculos/metabolismo , Hidrogéis
4.
Front Public Health ; 11: 1111661, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37006544

RESUMO

Comprehensive surveillance systems are the key to provide accurate data for effective modeling. Traditional symptom-based case surveillance has been joined with recent genomic, serologic, and environment surveillance to provide more integrated disease surveillance systems. A major gap in comprehensive disease surveillance is to accurately monitor potential population behavioral changes in real-time. Population-wide behaviors such as compliance with various interventions and vaccination acceptance significantly influence and drive the overall epidemic dynamics in the society. Original infoveillance utilizes online query data (e.g., Google and Wikipedia search of a specific content topic such as an epidemic) and later focuses on large volumes of online discourse data about the from social media platforms and further augments epidemic modeling. It mainly uses number of posts to approximate public awareness of the disease, and further compares with observed epidemic dynamics for better projection. The current COVID-19 pandemic shows that there is an urgency to further harness the rich, detailed content and sentiment information, which can provide more accurate and granular information on public awareness and perceptions toward multiple aspects of the disease, especially various interventions. In this perspective paper, we describe a novel conceptual analytical framework of content and sentiment infoveillance (CSI) and integration with epidemic modeling. This CSI framework includes data retrieval and pre-processing; information extraction via natural language processing to identify and quantify detailed time, location, content, and sentiment information; and integrating infoveillance with common epidemic modeling techniques of both mechanistic and data-driven methods. CSI complements and significantly enhances current epidemic models for more informed decision by integrating behavioral aspects from detailed, instantaneous infoveillance from massive social media data.


Assuntos
COVID-19 , Humanos , COVID-19/epidemiologia , SARS-CoV-2 , Pandemias , Infodemiologia , Atitude
5.
Crit Rev Food Sci Nutr ; 63(9): 1277-1292, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-34382897

RESUMO

As the second most abundant trace element in the human body, zinc nutrition is constantly a hot topic. More than one-third population is suffering zinc deficiency, which results in various types of diseases or nutritional deficiencies. Traditional ways of zinc supplementation seem with low absorption rates and significant side effects. Zinc supplements with dietary components are easily accessible and improve zinc utilization rate significantly. Also, mechanisms of maintaining zinc homeostasis are of broad interest. The present review focuses on zinc nutrition in human health in inductive methods. Mainly elaborate on different diseases relating to zinc disorder, highlighting the impact on the immune system and the recent COVID-19. Then raise food-derived zinc-binding compounds, including protein, peptide, polysaccharide, and polyphenol, and also analyze their possibilities to serve as zinc complementary. Finally, illustrate the way to maintain zinc homeostasis and the corresponding mechanisms. The review provides data information for maintaining zinc homeostasis with the food-derived matrix.


Assuntos
COVID-19 , Desnutrição , Humanos , Zinco , COVID-19/prevenção & controle , Dieta , Suplementos Nutricionais , Estado Nutricional
6.
Crit Rev Food Sci Nutr ; 63(25): 7627-7637, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-35258351

RESUMO

The second abundant micronutrient, zinc, is attracting more and more attention for it performs essential functions in living organisms and bears close relationships with the occurrence of diseases. However, excess zinc is toxic to cells. Ensuring a balanced zinc state for organisms is essential. Zinc transporters, including ZIPs and ZnTs, are pivotal in regulating zinc homeostasis. Benefiting from zinc transporter structures determination and their transporting dynamic revelation, the clarification of detailed mechanisms of zinc trafficking and the maintenance of zinc homeostasis by transporters in the human body are getting more and more evident. The present review gives a detailed description of the structural basis of zinc transport through ZIP and ZnT, through which the molecular mechanism of zinc binding and transport was illustrated. Then the motive force that drives zinc transmembrane transport and finally a generalization for the regulation models of zinc transporters were summarized.


Assuntos
Proteínas de Transporte de Cátions , Oligoelementos , Humanos , Proteínas de Transporte de Cátions/química , Proteínas de Transporte de Cátions/metabolismo , Homeostase , Zinco/metabolismo , Oligoelementos/metabolismo
7.
ACS Nano ; 16(11): 19472-19481, 2022 11 22.
Artigo em Inglês | MEDLINE | ID: mdl-36315654

RESUMO

Engineering proteins to construct self-assemblies is of crucial significance not only for understanding the sophisticated living systems but also for fabricating advanced materials with unexplored functions. However, due to the inherent chemical heterogeneity and structural complexity of the protein surface, designing complex protein assemblies in an anisotropic fashion remains challenging. Here, we describe a self-assembly approach to fabricating protein origami with a networklike structure by designing dual noncovalent interactions on the different positions of a single protein building block. With dimeric proteins as building blocks, 1D protein filaments were constructed by the designed metal coordination at key protein interfaces. Subsequently, the network superstructures were created by the cross-linking of the 1D protein filaments at branch point linkages through the second designed π-π stacking interactions. Notably, upon increasing the protein concentration, the formed protein networks convert into hydrogels with reversible, injectable, and self-healing properties, which have the ability to promote bone regeneration. This strategy could be used to fabricate other protein-based materials with unexplored functions.


Assuntos
Hidrogéis , Proteínas , Polímeros/química , Metais/química , Engenharia de Proteínas
8.
ACS Appl Mater Interfaces ; 14(39): 44125-44135, 2022 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-36162135

RESUMO

Reversible sol-gel transforming behaviors combined with tunable mechanical properties are vital demands for developing biomaterials. However, it remains challenging to correlate these properties with the hydrogels constructed by denatured protein as building blocks. Herein, taking advantage of naturally high-affinity coordination environments consisting of i, i + 4 His-Glu motifs offered by paramyosin, a ubiquitous nanofibrous protein, we found that Zn2+ rather than Ca2+ or Mg2+ has the ability to trigger the self-assembly of native abalone paramyosin (AbPM) into protein hydrogels under benign conditions, while the addition of EDTA induces the hydrogels back into protein monomers, indicative of a reversible process. By using such sol-gel reversible property, the AbPM gels can serve as a vehicle to encapsulate bioactive molecules such as curcumin, thereby protecting it from degradation from thermal and photo treatment. Notably, based on the high conserved structure of native AbPM, the mechanical property and biological activity of the fabricated AbPM hydrogels can be fined-tuned by its noncovalent interaction with small molecules. All these findings raise the possibility that native paramyosin can be explored as a new class of protein hydrogels which exhibit favorable properties that the traditional hydrogels constructed by denatured protein building blocks do not have.


Assuntos
Curcumina , Nanofibras , Materiais Biocompatíveis , Ácido Edético , Hidrogéis/química , Nanofibras/química , Tropomiosina
9.
Eur J Cancer Prev ; 31(6): 523-529, 2022 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-35044988

RESUMO

Lung cancer is the second common cancer and a leading cause of cancer-related death in the US. Unfavorably, the prevalence of using low-dose computed tomography (LDCT) for lung cancer prevention in the US has remained below 4% over time. The purpose of this study is to develop machine learning models to analyze interactive pathways of factors associated with lung cancer screening use with the LDCT. The study was based on the data retrieved from the 2018 Behavioral Risk Factor Surveillance System. After dealing with missing values, 86 variables and 710 samples were included in the decision tree model and the random forest model. The data were randomly split into training (569/710, 80%) and testing (141/710, 20%) sets. Gini impurity is used to select and determine the optimal split of the nodes in the model. Machine learning performance was evaluated by model accuracy, sensitivity, specificity, F1 score, etc. The average performance metrics of the decision tree model were obtained: average accuracy is 67.78%, F1 score is 65.76%, sensitivity is 62.52%, and specificity is 73.57% based on 100 runs. In the decision model, nine interactive pathways were identified among the following factors: average drinks per month, BMI, diabetes, first smoke age, years of smoking, year(s) quit smoking, sex, last sigmoidoscopy or colonoscopy, last dental visit, general health, insurance, education, and last Pap test. Lung cancer screening utilization is the result of the interplay of multifactors. Lung cancer screening programs in clinical settings should not only focus on patients' smoking behaviors but also consider other socioeconomic factors.


Assuntos
Detecção Precoce de Câncer , Neoplasias Pulmonares , Detecção Precoce de Câncer/métodos , Humanos , Neoplasias Pulmonares/diagnóstico por imagem , Neoplasias Pulmonares/epidemiologia , Aprendizado de Máquina , Programas de Rastreamento , Fumaça , Tomografia Computadorizada por Raios X/métodos
10.
Anal Chim Acta ; 1127: 149-155, 2020 Aug 29.
Artigo em Inglês | MEDLINE | ID: mdl-32800118

RESUMO

Methylmercury (MeHg+) as one of the most potent neurotoxins is mainly accumulated in brain, so in vivo imaging detection of MeHg+ in brain is of crucial importance. Herein, we reported a photoluminescent nanosensor for MeHg+ detection in brain by integrating the bioimaging of gold nanoclusters (Au NCs), the fluorescence of Au NCs quenched by MeHg+, and the brain targeting feature of our recently constructed 16-mer shell-like protein (7A). First, Au NCs with 7A as a biotemplate (7A-Au NCs) by a facile and green method in water are fabricated for the first time, the fluorescence of which (∼650 nm) can be quenched by MeHg+ in a dose-dependent manner in vitro. Second, the as-prepared 7A-Au NCs are not only suitable for bioimaging of BBB endothelial cells, but also are an effective probe for bioimaging MeHg+ detection in a brain-specific manner. These findings open a door for MeHg+ detection in the brain of living subjects.


Assuntos
Nanopartículas Metálicas , Compostos de Metilmercúrio , Animais , Encéfalo/diagnóstico por imagem , Células Endoteliais , Ferritinas , Ouro , Camundongos
11.
Int J Biol Macromol ; 142: 693-704, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31739063

RESUMO

The present study aimed to evaluate effect of Ganoderma atrum polysaccharide (PSG) on acute lung injury (ALI) rats and its mechanisms. Results showed that PSG exhibited protective effects against ALI by maintaining pulmonary histology, reducing levels of pro-inflammatory cytokines and NO both in serum and lung tissue. Moreover, this study further evaluated the metabolic effects of PSG based on UPLC-Triple-TOF/MS metabolomics analysis in rats. Compared with control group, LysoPC (18:2), LPA (18:1), taurocholic acid, L-histidine, and L-tryptophan were identified as metabolic biomarkers in serum of ALI group. Furthermore, biological pathways analysis demonstrated that histidine metabolism, nitrogen metabolism, tryptophan and part glycerophospholipids metabolism were notably modified by PSG treatment in ALI rats. Additionally, improved gut microbial metabolite short-chain fatty acids were found after intake of PSG in ALI rat. Altogether, PSG could control ALI-induced aberrant inflammation and its mechanisms were linked to inhibit release of pro-inflammatory mediators and reverse metabolic pathway disturbances.


Assuntos
Lesão Pulmonar Aguda/tratamento farmacológico , Lesão Pulmonar Aguda/prevenção & controle , Anti-Inflamatórios/química , Ganoderma/química , Polissacarídeos/química , Animais , Anti-Inflamatórios/farmacologia , Biomarcadores/sangue , Biomarcadores/metabolismo , Cromatografia Líquida de Alta Pressão , Citocinas/sangue , Citocinas/metabolismo , Modelos Animais de Doenças , Ácidos Graxos Voláteis/metabolismo , Histidina/sangue , Histidina/metabolismo , Lisofosfatidilcolinas/sangue , Lisofosfatidilcolinas/metabolismo , Lisofosfolipídeos/sangue , Lisofosfolipídeos/metabolismo , Masculino , Metabolômica , Polissacarídeos/farmacologia , Ratos , Ratos Sprague-Dawley , Transdução de Sinais , Espectrometria de Massas em Tandem , Ácido Taurocólico/sangue , Ácido Taurocólico/metabolismo , Triptofano/sangue , Triptofano/metabolismo
12.
Biomed Pharmacother ; 121: 109588, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31707350

RESUMO

Translocator protein (TSPO) is highly expressed in the cardiovascular system, exerting crucial effects on both myocardial damage and protection. However, the role and mechanism of TSPO in myocardial ischemia/reperfusion (I/R) injury remains elusive. In the current study, we subjected H9c2 cardiomyocytes to anoxia/reoxygenation (A/R) and knocked down TSPO expression by RNA interference to investigate the possible mechanism of TSPO on I/R injury. TSPO expression in cardiomyocytes was up-regulated when exposed to A/R, but normal in anoxic preconditioned (APC) cardiomyocytes. Moreover, A/R also led to an increase in reactive oxygen species (ROS), oxidative stress aggravation, mitochondrial membrane potential collapse, mitochondrial permeability transition pore (mPTP) opening, and cell apoptosis. However, these events were completely compensated by downregulating TSPO expression. TSPO-downregulated cardiomyocytes produced lesser lactate dehydrogenase (LDH) and creatine phosphokinase (CPK), and showed lesser cytosol malondialdehyde (MDA) accumulation than normal cells after A/R injury. On the other hand, the TSPO- downregulated cells showed higher activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), mitochondrial function stabilization, resulting in less cell apoptosis and damage in case of A/R condition. In conclusion, TSPO expression is up-regulated under A/R injury, whereas repression of TSPO improves the endurance of cardiomyocytes against A/R injury by reducing oxidative stress, mitochondrial damage and cell apoptosis.


Assuntos
Proteínas de Transporte/biossíntese , Regulação para Baixo/fisiologia , Homeostase/fisiologia , Mitocôndrias/metabolismo , Miócitos Cardíacos/metabolismo , Estresse Oxidativo/fisiologia , Receptores de GABA-A/biossíntese , Animais , Proteínas de Transporte/genética , Hipóxia Celular/fisiologia , Linhagem Celular , Expressão Gênica , Ratos , Espécies Reativas de Oxigênio/metabolismo , Receptores de GABA-A/genética
13.
Artigo em Inglês | MEDLINE | ID: mdl-31744075

RESUMO

Simultaneous ecological and health risk assessments of potentially toxic elements in soils and sediments can provide substantial information on their environmental influence at the river-basin scale. Herein, soil and sediment samples were collected from the Guishui River basin to evaluate the pollution situation and the ecological and health risk of potentially toxic elements. Various indexes were utilized for quantitatively assessing their health risks. Pollution assessment by geo-accumulation index showed that Cd had "uncontaminated to moderately polluted" status in the soils and sediments. Potential ecological risk index showed that the Guishui River basin was at low risk in general, but Cd was classified as "moderate or considerable ecological risk" both in the soils and sediments. Health risk assessment calculated human exposure from soils and indicated that both non-carcinogenic and carcinogenic risks of the selected potentially toxic elements were lower than the acceptable levels. Health risks posed by potentially toxic elements bio-accumulated in fish, stemming from sediment resuspension, were also assessed. Non-carcinogenic hazard index indicated no adverse health effects on humans via exposure to sediments; however, in general, Cr contributed largely to health risks among the selected potentially toxic elements. Therefore, special attention needs to be paid to the Guishui River basin in the future.


Assuntos
Sedimentos Geológicos/química , Rios/química , Poluentes do Solo/química , Solo/química , Poluentes Químicos da Água/química , Animais , Pequim , Monitoramento Ambiental , Poluição Ambiental , Peixes , Humanos , Metais Pesados/análise , Medição de Risco
14.
Food Funct ; 10(11): 7227-7238, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31616874

RESUMO

This study aimed at exploring the role of a Ganoderma atrum polysaccharide (PSG-1) in pancreatic damage in streptozotocin (STZ)-induced type 1 diabetes mellitus (T1DM) mice. The results suggested that blood glucose was significantly increased in the STZ group in comparison with the control group. After 4 weeks of treatment with PSG-1 or metformin (MET), blood glucose levels in the PSG-1 and MET groups were apparently lower than in the STZ group, indicating that PSG-1 triggered hypoglycemic effects in vivo. Moreover, experiments demonstrated that PSG-1 markedly decreased apoptosis of islet cells by inhibiting the mitochondrial apoptotic pathway and activating the PI3K/Akt survival pathway. PSG-1 also exerted anti-inflammatory effects, as evidenced by the dramatically decreased levels of IL-1ß, TNF-α and INF-γ and restraint of the TLR4-dependent NF-κB signal pathway. Meanwhile, PSG-1 maintained homeostasis of redox systems by increasing the activities of anti-oxidant enzymes and decreasing the amount of malondialdehyde in the pancreas. Together, these data provide evidence that PSG-1 can be employed as an alternative dietary supplement to ameliorate T1DM.


Assuntos
Diabetes Mellitus Experimental/tratamento farmacológico , Ganoderma/metabolismo , Pâncreas/efeitos dos fármacos , Polissacarídeos/farmacologia , Animais , Apoptose/efeitos dos fármacos , Glicemia , Relação Dose-Resposta a Droga , Peroxidação de Lipídeos/efeitos dos fármacos , Masculino , Camundongos , Mitocôndrias/metabolismo , Pâncreas/citologia , Polissacarídeos/administração & dosagem , Espécies Reativas de Oxigênio
15.
Food Funct ; 10(5): 2986-2996, 2019 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-31074758

RESUMO

Necrotizing enterocolitis (NEC) is a serious intestinal disease associated with a high mortality (40-60%) in newborn infants. Cronobacter sakazakii is an important factor for NEC. However, studies regarding NEC pathogenesis and therapeutic treatments are still limited. Here, a C. sakazakii-induced mouse neonatal intestinal inflammation model was employed to determine the effects of trans-cinnamaldehyde (TC) on infections. TC treatment reduced the number of C. sakazakii colony-forming units in the ileal tissues and mitigated the morphological damage in intestinal tissues. Additionally, it reduced the mRNA transcription of inflammatory genes and production of interleukin 6 and tumor necrosis factor-α in mice infected with C. sakazakii. Moreover, TC treatment suppressed caspase-3 activity, modulated enterocyte apoptosis, and inhibited the nuclear factor-kappa B signaling pathway activation induced by C. sakazakii. These findings suggest that TC has protective effects on C. sakazakii-induced murine intestinal inflammation and that it may be a potential agent for preventing NEC.


Assuntos
Acroleína/análogos & derivados , Cronobacter sakazakii/fisiologia , Enterocolite Necrosante/tratamento farmacológico , Intestinos/imunologia , Acroleína/administração & dosagem , Acroleína/química , Animais , Animais Recém-Nascidos/imunologia , Animais Recém-Nascidos/microbiologia , Modelos Animais de Doenças , Enterocolite Necrosante/genética , Enterocolite Necrosante/imunologia , Enterocolite Necrosante/microbiologia , Feminino , Humanos , Interleucina-6/genética , Interleucina-6/imunologia , Intestinos/microbiologia , Isomerismo , Masculino , Camundongos , Fator de Necrose Tumoral alfa/genética , Fator de Necrose Tumoral alfa/imunologia
16.
Ecotoxicol Environ Saf ; 147: 342-348, 2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-28858707

RESUMO

As the largest man-made reservoir in China, the Three Gorges Reservoir (TGR) has significant influence on national drinking water safety. The geochemical behavior of trace elements at the sediment-water interface (SWI) is still unknown. The mobilization characteristics of trace elements (As, Mo and W)-determined by diffusive gradients in thin films (DGT)-were studied to quantitatively calculate the release trends in the SWI in three typical tributaries and the mainstream of the TGR in the summer. The results showed that concentrations of DGT-labile As, Mo and W in the overlying water and sediment cores showed significant variations in the ranges of 0.05-50.90, 0.30-1.63 and 0.01-0.42µgL-1, respectively. The apparent net diffusive fluxes were significantly positive in most sampling sites (77.8% for As, 88.8% for Mo and 66.6% for W), suggesting that the sediment was the source of these three elements. It was noteworthy that the maximum net diffusive fluxes of As and W were found in the upstream of Meixi tributary, which may be attributed to anthropogenic activities. In addition, As, Mo and W may be incorporated in Fe and Mn oxyhydroxides and these three elements simultaneously remobilized with Fe and Mn.


Assuntos
Arsênio/análise , Monitoramento Ambiental/métodos , Sedimentos Geológicos/química , Molibdênio/análise , Tungstênio/análise , Poluentes Químicos da Água/análise , China , Estações do Ano , Oligoelementos/análise , Recursos Hídricos
17.
Chemosphere ; 195: 390-397, 2018 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-29274578

RESUMO

The South-to-North Water Diversion Project has been initiated to address the problem of water shortages in north China. However, the environmental impact of this project is currently unclear, especially for the geochemical process of toxic trace metals in reservoir riparian soil following water submergence. The mobility of Ni in Miyun Reservoir riparian soil samples was investigated using diffusive gradients in thin films (DGT), considering five different land use types and three vertical elevations. The DGT-induced fluxes in soil (DIFS) model was applied to simulate the kinetics of Ni mobilization in the soil. The results showed that the average concentration of Ni was 36.58 mg/kg, which was slightly higher than the corresponding background values reported for both Beijing and China. Coincidentally, the highest concentrations of both total Ni and DGT-labile Ni (CDGT-Ni) were observed at the same site (recreational area), indicating that anthropogenic activities may have contributed to the release of Ni. Land use type and vertical elevation had no significant influence on CDGT-Ni. In addition, CDGT-Ni was positively correlated with reducible fraction, CDGT-Fe, CDGT-Mn, and TOC, indicating that Ni in the soils was adsorbed mainly on the Fe/Mn oxides and organic matter. Moreover, the low values of R (CDGT-Ni/Csol-Ni, R < 0.25) indicated that the replenishment of Ni from the solid phase was poor, and the rate of Ni desorption was considerably lower than its depletion rate, thus leaving only a small proportion of Ni was available.


Assuntos
Níquel/análise , Poluentes do Solo/análise , Solo/química , Oligoelementos/análise , Pequim , China , Monitoramento Ambiental/métodos , Atividades Humanas , Cinética , Níquel/química , Água
18.
Huan Jing Ke Xue ; 39(12): 5464-5472, 2018 Dec 08.
Artigo em Chinês | MEDLINE | ID: mdl-30628389

RESUMO

The Three Gorges Reservoir (TGR) has achieved the target of water storage of 175 m for eight consecutive years until October 2017. To study the temporal and spatial variation of nickel (Ni) in different water periods under 175 m operating conditions in the TGR area, probe the impact of a large-scale water conservancy project on the Ni enrichment, and establish the pollution evaluation system of Ni in the TGR area, we collected 173 surface sediment samples from the TGR area during four consecutive water periods from December 2015 to June 2017 and measured the Ni concentration by using inductively coupled plasma mass spectrometry (ICP-MS). The mean values of Ni in the four water periods are higher than the background value of Yangtze sediment and soil. At the spatial scale, the Ni content in the mainstream exhibits a clear upward trend from upstream to downstream and is lower than that of the tributary. The tributaries of the lower reaches shows a notably higher Ni content than the tributaries of the upper and middle reaches. At the temporal scale, the water period exerts an insignificant effect on the Ni content. The Ni content is relatively stable and shows a downward tendency at a 175 m water level. The regional geochemical baseline (RGB) value of Ni was obtained through building a geochemical baseline model in the area. The RGB values of Ni in sediments during four consecutive water periods are 47.0, 44.2, 42.9, and 41.9 mg·kg-1, respectively. The Ni contents in the middle and lower reaches of the mainstream and tributary are significantly affected by human activities. Moreover, the pollution evaluations based on global Ni background values, local background values, and geochemical baseline values as reference values were compared and the geoaccumulation index and potential ecological risk of Ni were determined to comprehensively assess its pollution risk. The assessment data indicate that Ni in the aquatic environment of the TGR area is almost uncontaminated and poses a low ecological risk, except for samples in regions around Fengdu County and Guizhou Town in the Zigui County along the mainstream, which were uncontaminated to moderately contaminated. Relative to global and regional background values, the pollution assessment results obtained using the RGB as a reference value are more scientific and better match the temporal and spatial variation of the study area.

19.
Environ Sci Pollut Res Int ; 24(26): 20844-20858, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28815359

RESUMO

The Three Gorges Dam in China is the world's largest dam. Upon its completion in 2003, the Three Gorges Reservoir (TGR) became the largest reservoir in China and plays an important role in economic development and national drinking water safety. However, as a sink and source of heavy metals, there is a lack of continuous and comparative data on heavy metal pollution in sediments. This study reviewed all available literatures published on heavy metals in TGR sediments and further provided a comprehensive assessment of the pollution tendency of these heavy metals. The results showed that heavy metal concentrations in TGR sediments varied spatially and temporally. Temporal variations indicated that Hg in tributaries, as well as As, Cd, Cr, Cu, Ni, Pb, and Zn in the mainstream, exhibited a higher probability to exceed background values after the impoundment of TGR. Pollution assessments by contamination factor, geoaccumulation index, and potential ecological risk were similar. High Cd and Hg concentrations in both the mainstream and tributaries are a cause for much concern. However, sediment quality guidelines produced different results, as most previous studies adopted different sampling and measurement strategies. The data inconsistencies and lack of continuity regarding the reservoir confirm the need for a continuous monitoring network and the development of quality criteria relevant to the sediments of the TGR in the future.


Assuntos
Sedimentos Geológicos/química , Metais Pesados/análise , Poluentes Químicos da Água/análise , Abastecimento de Água , China , Monitoramento Ambiental/métodos , Poluição Ambiental , Mercúrio/análise , Medição de Risco , Rios
20.
Environ Pollut ; 218: 1094-1101, 2016 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-27613314

RESUMO

The Three Gorges Reservoir (TGR) is the largest reservoir in China. Cadmium (Cd) is a primary pollutant in the TGR, and its speciation and bioavailability have attracted extensive attention since TGR submergence. In this study, Chelex-100 DGT (diffusive gradient in thin films) and the sequential extraction method were used to investigate the bioavailable Cd in sediments obtained from a typical tributary (Meixi) and mainstream (Yangtze) in the TGR. The total Cd concentrations in sediments of the four stations were also determined. In comparison to the concentrations of labile Cd measured by DGT (CDGT-Cd) in four profiles, CJ and MX-upstream/downstream were at potential risk for Cd release from surface sediments using the apparent diffusion flux across the interface numerical model. The order of CDGT-Cd in surface sediments was as follows: CJ > MX-downstream > MX-upstream > MX-midstream. Additionally, a positive correlation was demonstrated between CDGT-Cd and Cd in the exchangeable fraction (F1) in the surface sediments, indicating that Cd in the exchangeable fraction was readily captured by DGT. A negative correlation was observed between CDGT-Cd and CDGT-Fe, CDGT-Mn in the sediment-water-interface (SWI), suggesting that Fe/Mn oxides did not control the release of labile-Cd from sediments. Furthermore, a positive correlation existed between the CDGT-Cd in the surface sediments and Cd in the oxidizable fraction (F3), illustrating that Cd sorbed or bound with organic matter or sulfide was labile and released into the water phase from the surface sediments. A dark area was found in the AgI gel, which further demonstrated that Cd simultaneously was released with sulfide in this area.


Assuntos
Cádmio/análise , Monitoramento Ambiental/métodos , Sedimentos Geológicos/análise , Rios/química , Poluentes Químicos da Água/análise , China , Monitoramento Ambiental/instrumentação , Sulfetos/análise
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