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1.
Front Bioeng Biotechnol ; 12: 1392269, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-39100623

RESUMO

Improvements in digital microscopy are critical for the development of a malaria diagnosis method that is accurate at the cellular level and exhibits satisfactory clinical performance. Digital microscopy can be enhanced by improving deep learning algorithms and achieving consistent staining results. In this study, a novel miLab™ device incorporating the solid hydrogel staining method was proposed for consistent blood film preparation, eliminating the use of complex equipment and liquid reagent maintenance. The miLab™ ensures consistent, high-quality, and reproducible blood films across various hematocrits by leveraging deformable staining patches. Embedded-deep-learning-enabled miLab™ was utilized to detect and classify malarial parasites from autofocused images of stained blood cells using an internal optical system. The results of this method were consistent with manual microscopy images. This method not only minimizes human error but also facilitates remote assistance and review by experts through digital image transmission. This method can set a new paradigm for on-site malaria diagnosis. The miLab™ algorithm for malaria detection achieved a total accuracy of 98.86% for infected red blood cell (RBC) classification. Clinical validation performed in Malawi demonstrated an overall percent agreement of 92.21%. Based on these results, miLab™ can become a reliable and efficient tool for decentralized malaria diagnosis.

3.
Nat Commun ; 15(1): 7598, 2024 Aug 31.
Artigo em Inglês | MEDLINE | ID: mdl-39217169

RESUMO

Atmospheric mercury (Hg(0), Hg(II)) and riverine exported Hg (Hg(II)) are proposed as important Hg sources to the Arctic Ocean. As plankton cannot passively uptake Hg(0), gaseous Hg(0) has to be oxidized to be bioavailable. Here, we measured Hg isotope ratios in zooplankton, Arctic cod, total gaseous Hg, sediment, seawater, and snowpack from the Bering Strait, the Chukchi Sea, and the Beaufort Sea. The Δ200Hg, used to differentiate between Hg(0) and Hg(II), shows, on average, 70% of Hg(0) in all biota and differs with seawater Δ200Hg (Hg(II)). Since Δ200Hg anomalies occur via tropospheric Hg(0) oxidation, we propose that near-surface Hg(0) oxidation via terrestrial vegetation, coastally evaded halogens, and sea salt aerosols, which preserve Δ200Hg of Hg(0) upon oxidation, supply bioavailable Hg(II) pools in seawater. Our study highlights sources and pathways in which Hg(0) poses potential ecological risks to the Arctic Ocean biota.

4.
Mar Pollut Bull ; 205: 116602, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38950512

RESUMO

The potential effect of hydrological conditions on distribution and loadings of Hg species was investigated in the microtidal Hyeongsan River Estuary (HRE). Dissolved Hg (DHg) and dissolved methylmercury (DMeHg) from the creek receiving industrial wastes were effectively settled to sediment during the post-typhoon period, while persistent input from the Hg-contaminated creek without settling was observed during the dry periods. The event-based mean approach was applied to explore the hydrological effects on the annual flux of Hg. The largest inputs of DHg and particulate Hg (PHg) were found in the Hg-contaminated creek, and DHg input was higher in the dry than wet periods whereas PHg input was higher in the wet than dry periods. In sediment, Hg and MeHg concentrations decreased after the typhoon, attributed to erosion of surface sediments. Overall, the HRE serves as an effective sink of Hg that reduces the degree of Hg contamination in coastal water.


Assuntos
Monitoramento Ambiental , Estuários , Sedimentos Geológicos , Hidrologia , Mercúrio , Rios , Poluentes Químicos da Água , Mercúrio/análise , Poluentes Químicos da Água/análise , Rios/química , Sedimentos Geológicos/química , Compostos de Metilmercúrio/análise
5.
ACS Nano ; 2024 Jul 16.
Artigo em Inglês | MEDLINE | ID: mdl-39012788

RESUMO

Chemiresistive gas sensors based on semiconducting metal oxides typically rely on noble metal catalysts to enhance their sensitivity and selectivity. However, noble metal catalysts have several drawbacks for practical utilization, including their high cost, their propensity for spontaneous agglomeration, and poisoning effects with certain types of gases. As such, in the interest of commercializing the chemiresistive gas sensor technology, we propose an alternative design for a noble-metal-free sensing material through the case study of Co-doped ceria (Co-CeO2) catalysts embedded in a SnO2 matrix. In this investigation, we utilized electrospinning and subsequent calcination to prepare Co-CeO2 catalyst nanoparticles integrated with SnO2 nanofibers (NFs) with uniform particle distribution and particle size regulation down to the sub-2 nm regime. The resulting Co-CeO2@SnO2 NFs exhibited superior gas sensing characteristics toward isoprene (C5H8) gas, a significant biomarker for monitoring the onset of various diseases through breath diagnostics. In particular, we identified that the Co-CeO2 catalysts, owing to the transition metal doping, facilitated the spillover of chemisorbed oxygen species to the SnO2 sensing body. This resulting in the sensor having a 27.4-fold higher response toward 5 ppm of C5H8 (compared to pristine SnO2), exceptionally high selectivity, and a low detection limit of 100 ppb. The sensor also exhibited high stability for prolonged response-recovery cycles, attesting to the strong anchoring of Co-CeO2 catalysts in the SnO2 matrix. Based on our findings, the transition metal-doped metal oxide catalysts, such as Co-CeO2, demonstrate strong potential to completely replace noble metal catalysts, thereby advancing the development of the commercially viable chemiresistive gas sensors free from noble metals, capable of detecting target gases at sub-ppm levels.

6.
Behav Sci (Basel) ; 14(5)2024 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-38785902

RESUMO

Mysterious consumption, characterized by product purchases without knowledge of their exact nature, is gaining popularity in the modern marketplace. In two online experiments, we examined how consumers' psychological states, particularly their sense of personal control, influence their perception and intent to purchase mysterious products in the context of purchasing a random flight ticket. Study 1 demonstrated that when consumers experience low personal control, as opposed to high personal control, they are less likely to value the uncertainty inherent in random flight tickets, resulting in decreased purchase intentions. Study 2 revealed that introducing even limited choice options to random flight tickets can enhance consumers' appreciation of uncertainty, thereby increasing their purchase intention. This effect was especially notable among those initially hesitant to embrace uncertainty, ultimately boosting their intent to purchase. These findings deepen our understanding of consumer psychology surrounding mystery consumption and provide practical insights for marketers seeking to tailor their products and marketing appeals to consumers' psychological states.

7.
Sci Total Environ ; 932: 173090, 2024 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-38729360

RESUMO

The understanding of the essential environmental factors affecting the spatiotemporal variation in methylmercury (MeHg) in river water is limited to date, despite its importance for predicting the effect of ongoing climate change on MeHg accumulation in freshwater ecosystems. This study aimed to explore the variation in MeHg concentration and related environmental factors in the downstream zone of the Yeongsan River under highly dynamic hydrologic conditions by using water quality and hydrologic data collected from 1997 to 2022, and Hg and MeHg data collected from 2017 to 2022. The mean concentration of unfiltered MeHg was 35.7 ± 13.7 pg L-1 (n = 24) in summer and 26.7 ± 7.43 pg L-1 (n = 24) in fall. Dissolved oxygen (DO), conductivity, nitrate, and dissolved organic carbon (DOC) were determined to be the most influential variables in terms of MeHg variation based on the partial least squares regression model, and their effects on the MeHg concentration were negative, except for DOC. Heatmaps representing the similarity distances between temporal trends of hydrologic and water quality variables were constructed to determine fundamental factors related to the time-based variations in DO, conductivity, nitrate, and DOC using a dynamic time warping algorithm. The heatmap cluster analysis showed that the temporal trends of these variables were closely related to rainfall variation rather than irradiance or water temperature. Overall, biogeochemical factors directly related to in situ methylation rate of Hg(II)-rather than transport of Hg(II) and MeHg from external sources-mainly control the spatiotemporal variation of MeHg in the downstream zone of the Yeongsan River.

8.
J Adv Prosthodont ; 16(2): 105-114, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38694193

RESUMO

PURPOSE: This study aimed to evaluate the effect of pretreatment of three different universal adhesives (Single Bond Universal [SBU], All-Bond Universal [ABU], and Prime&Bond universal [PBU]) on the bonding durability of an adhesive (Panavia F 2.0, PF) and a conventional (Duo-Link, DL) resin cements to air-abraded zirconia. MATERIALS AND METHODS: Rectangular-shaped zirconia specimens were prepared. The chemical composition and surface energy parameters of the materials were studied by Fourier transform infrared spectroscopy and contact angle measurement, respectively. To evaluate resin bonding to the zirconia, all the bonding specimens were immersed in water for 24 h and the specimens to be aged were additionally thermocycled 10000 times before the shear bond strength (SBS) test. RESULTS: The materials showed different surface energy parameters, including the degree of hydrophilicity/hydrophobicity. While the DL/CON (no pretreatment) showed the lowest SBS and a significant decrease in the value after thermocycling (P < .001), the PF/CON obtained a higher SBS value than the DL/CON (P < .001) and no decrease even after thermocycling (P = .839). When the universal adhesives were used with DL, their SBS values were higher than the CON (P < .05), but the trend was adhesive-specific. In conjunction with PF, the PF/SBU produced the highest SBS followed by the PF/ABU (P = .002), showing no significant decrease after thermocycling (P > .05). The initial SBS of the PF/PBU was similar to the PF/CON (P = .999), but the value decreased after thermocycling (P < .001). CONCLUSION: The universal adhesive pretreatment did not necessarily show a synergistic effect on the bonding performance of an adhesive resin cement, whereas the pretreatment was beneficial to bond strength and durability of a conventional resin cement.

9.
ACS Appl Mater Interfaces ; 16(13): 16853-16860, 2024 Apr 03.
Artigo em Inglês | MEDLINE | ID: mdl-38501934

RESUMO

In this work, we designed a multimodal transformer that combines both the Simplified Molecular Input Line Entry System (SMILES) and molecular graph representations to enhance the prediction of polymer properties. Three models with different embeddings (SMILES, SMILES + monomer, and SMILES + dimer) were employed to assess the performance of incorporating multimodal features into transformer architectures. Fine-tuning results across five properties (i.e., density, glass-transition temperature (Tg), melting temperature (Tm), volume resistivity, and conductivity) demonstrated that the multimodal transformer with both the SMILES and the dimer configuration as inputs outperformed the transformer using only SMILES across all five properties. Furthermore, our model facilitates in-depth analysis by examining attention scores, providing deeper insights into the relationship between the deep learning model and the polymer attributes. We believe that our work, shedding light on the potential of multimodal transformers in predicting polymer properties, paves a new direction for understanding and refining polymer properties.

10.
Plast Surg (Oakv) ; 32(1): 108-112, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38433812

RESUMO

Introduction: Rapid climate change poses a major challenge to healthcare. The operating room is especially responsible for carbon emission, with 20% to 70% of hospital waste traced back to the operating room. This literature review aims to suggest changes that can be made in hand surgery for a more sustainable practice. Methods: A literature search was conducted from PubMed, Medline, and other online search engines with the keywords "carbon footprint, environmental health, carbon neutral, plastic surgery, hand surgery, surgery." Results: "Reduce, Reuse, Recycle, Research, Rethink and Culture" was the framework used to recommend a more carbon neutral practice. In reduction, techniques such as cutting down oversupply of materials, adopting protocols to perform cases in ambulatory settings, and simple measures to reduce energy were identified as valuable methods. Modified sterilization techniques and reprocessing single-use devices were techniques identified for reuse and recycling involved single-stream recycling, staff training, and donation of basic surgical supplies. Research involved adopting data-driven programs for life cycle assessment of all equipment in the operating room, while the use of telemedicine and "green meetings' were suggested for rethinking. Finally, strategies to encourage a team approach to environmental responsibility were discussed. Conclusion: Carbon neutral practice must be implemented to safeguard sustainable and cost-effective operating rooms and healthcare systems. Hand surgery can pave the way for other specialties through the use of available resources to develop guidelines for carbon neutral practice. This requires active effort from hand surgeons to act as role models for other healthcare professionals.


Introduction : Les changements climatiques rapides constituent un défi majeur pour les soins de santé. La salle d'opération est particulièrement responsable de l'émission de carbone avec 20% à 70% des déchets hospitaliers rapportés aux salles d'opération. Cette revue de la littérature vise à suggérer les changements qui peuvent être apportés dans la chirurgie de la main pour une pratique plus durable. Méthodes : Une recherche bibliographique a été menée dans les bases de données PubMed, Medline et autres moteurs de recherche en ligne avec les mots-clés suivants : empreinte carbone, santé environnementale, carbone neutre, chirurgie plastique, chirurgie de la main et chirurgie. Résultats : « Réduire, Réutiliser, Recycler, Rechercher, Repenser et Culture ¼ a été le cadre utiliser pour recommander une pratique plus neutre en matière de carbone. Sous « réduction ¼, des techniques telles que des coupures dans l'excès d'approvisionnement en matériaux, l'adoption de protocoles permettant de traiter des cas en ambulatoire et des mesures simples pour réduire la consommation d'énergie sont des méthodes qui ont été jugées utiles. Des techniques de stérilisation modifiées et de retraitement de dispositifs à usage unique sont des techniques identifiées pour la réutilisation; le recyclage a impliqué une collecte en vrac, la formation du personnel et le don de fournitures chirurgicales de base. La recherche a nécessité d'adopter des programmes pilotés sur des données pour l'évaluation du cycle de vie de tout équipement de la salle de l'opération pendant que le recours à la télémédecine et aux réunions respectueuses de l'environnement était suggéré pour le thème « repenser ¼. Enfin, des stratégies visant à encourager une approche d'équipe envers la responsabilité environnementale ont été discutées. Conclusion : Une pratique carbone neutre doit être mise en œuvre pour protéger les salles d'opération durables et rentables ainsi que les systèmes de soins de santé. La chirurgie de la main peut ouvrir la voie à d'autres spécialités par l'utilisation des ressources disponibles afin d'élaborer des lignes directrices pour l'empreinte carbone de la pratique. Cela nécessite un effort de la part des chirurgiens de la main pour devenir des exemples pour les autres professionnels de santé.

11.
Mar Pollut Bull ; 202: 116300, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38555803

RESUMO

This study investigated the contents of total mercury (THg), trace metals, and CH4 and determined the signature microbes involved in various biogeochemical processes in the sediment of the Canadian Beaufort Sea. The THg ranged between 32 and 63 µg/kg and the trace metals such as Fe, Al, Mn, and Zn were significant in distributions. The pH, SO42-, Fe2+, and redox proxy metals were crucial factors in the spatial and vertical heterogeneity of geochemical distributions. CH4 was detected only at the mud volcano site. Microbial analyses identified Clostridium, Desulfosporosinus, Desulfofustis, and Desulftiglans as the predominant Hg methylators and sulfate reducers; Nitrosopumilus and Hyphomicrobium as the major nitrifiers and denitrifiers; Methanosarcina and Methanosaeta as keystone methanogens; and Methyloceanibacter and Methyloprofundus as signature methanotrophs. Altogether, this study expands the current understanding of the microbiological and geochemical features and could be helpful in predicting ecosystem functions in the Canadian Beaufort Sea.


Assuntos
Sedimentos Geológicos , Mercúrio , Poluentes Químicos da Água , Sedimentos Geológicos/química , Sedimentos Geológicos/microbiologia , Mercúrio/análise , Mercúrio/metabolismo , Poluentes Químicos da Água/análise , Monitoramento Ambiental , Bactérias , Metano/análise , Canadá
12.
Environ Pollut ; 343: 123270, 2024 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-38163627

RESUMO

The cross-shelf distributions of total mercury (THg), methylmercury (MeHg) and organic and inorganic matter, as well as the presence of the hgcA gene were investigated on the East Siberian Shelf (ESS) to understand the processes underlying the speciation of sedimentary Hg. Samples were collected from 12 stations grouped into four zones based on water depth: inner shelf (5 stations), mid-shelf (3 stations), outer shelf (2 stations), and slope (2 stations). The THg concentration in the surface sediment increased from the inner shelf (0.25 ± 0.023 nmol g-1) toward the slope (0.52 nmol g-1), and, when normalized to total organic carbon content, the THg showed a positive correlation with the clay-to-sand ratio (r2 = 0.48, p = 0.012) and degree of chemical weathering (r2 = 0.79, p = 0.0001). The highest MeHg concentrations (3.0 ± 1.8 pmol g-1), as well as peaks in the S/C ratio (0.012 ± 0.002) of sediment-leached organic matter, were found on the mid-shelf, suggesting that the activities of sulfate reducers control the net Hg(II) methylation rates in the sediment. This was supported by results from a principal component analysis (PCA) performed with Hg species concentrations and sediment-leached organic matter compositions. The site-specific variation in MeHg showed the highest similarity with that of CHONS compounds in the PCA, where Deltaproteobacteria were projected to be putative Hg(II) methylators in the gene analysis. In summary, the hydrodynamic sorting of lithogenic particles appears to govern the cross-shelf distribution of THg, and in situ methylation is considered a major source of MeHg in the ESS sediment.


Assuntos
Mercúrio , Compostos de Metilmercúrio , Poluentes Químicos da Água , Mercúrio/análise , Sedimentos Geológicos/química , Poluentes Químicos da Água/análise , Monitoramento Ambiental/métodos , Compostos de Metilmercúrio/análise , Oceanos e Mares
13.
Mar Pollut Bull ; 200: 116035, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38271917

RESUMO

The supply and sources of N and Hg in the Geum estuary of the western coast of Korea were evaluated. Triple isotope proxies (δ15NNO3, Δ17ONO3 and δ18ONO3) of NO3- combined with conservative mixing between river and ocean waters were used to improve isotope finger-printing methods. The N pool in the Geum estuary was primarily influenced by the Yellow Sea water, followed by riverine discharge (821 × 106 mol yr-1) and atmospheric deposition (51 × 106 mol yr-1). The influence of the river was found to be greater for Hg than that of the atmosphere. The triple isotope proxies revealed that the riverine and atmospheric inputs of N have been affected by septic wastes and fossil fuel burning, respectively. From the inner estuary towards offshore region, the influence of the river diminishes, thus increasing the relative impact of the atmosphere. Moreover, the isotope proxies showed a significant influence of N assimilation in February and nitrification in May.


Assuntos
Mercúrio , Poluentes Químicos da Água , Isótopos de Nitrogênio/análise , Estuários , Ecossistema , Monitoramento Ambiental/métodos , Rios , Poluentes Químicos da Água/análise , Nitratos/análise
14.
J Med Chem ; 66(23): 16342-16363, 2023 12 14.
Artigo em Inglês | MEDLINE | ID: mdl-38031930

RESUMO

Janus kinase 1 (JAK1) plays a pivotal role in regulating inflammation and fibrosis via the JAK/STAT signaling pathway, making it a promising target for associated diseases. In this study, we explored the modification of an N-methyl 1H-pyrrolo[2,3-b]pyridine-5-carboxylate core, leading to the identification of 4-(((2S,4S)-1-(4-trifluoromethyl)-2-methylpiperidin-4-yl)amino)-N-methyl-1H-pyrrolo[2,3-b]pyridine-5-carboxamide (36b) as a highly potent and selective JAK1 inhibitor. Compound 36b exhibited an impressive IC50 value of 0.044 nM for JAK1 and demonstrated remarkable selectivity of 382-fold, 210-fold, and 1325-fold specificity over JAK2, JAK3, and TYK2, respectively. The kinase panel assays further confirmed its specificity, and cell-based experiments established its efficacy in inhibiting JAK1-STAT phosphorylation in human L-132 or SK-MES-1 cells. Pharmacokinetic studies revealed that compound 36b boasts an oral bioavailability exceeding 36%. In a bleomycin-induced fibrosis mouse model, compound 36b significantly reduced STAT3 phosphorylation, resulting in improvement in body weight and reduced collagen deposition, all achieved without significant side effects.


Assuntos
Inibidores de Janus Quinases , Fibrose Pulmonar , Camundongos , Animais , Humanos , Relação Estrutura-Atividade , Inibidores de Proteínas Quinases/farmacologia , Fibrose Pulmonar/induzido quimicamente , Fibrose Pulmonar/tratamento farmacológico , Inibidores de Janus Quinases/farmacologia , Janus Quinase 1 , Piridinas
15.
J Chem Inf Model ; 63(18): 5755-5763, 2023 09 25.
Artigo em Inglês | MEDLINE | ID: mdl-37683188

RESUMO

New solid-state materials have been discovered using various approaches from atom substitution in density functional theory (DFT) to generative models in machine learning. Recently, generative models have shown promising performance in finding new materials. Crystal generation with deep learning has been applied in various methods to discover new crystals. However, most generative models can only be applied to materials with specific elements or generate structures with random compositions. In this work, we developed a model that can generate crystals with desired compositions based on a crystal diffusion variational autoencoder. We generated crystal structures for 14 compositions of three types of materials in different applications. The generated structures were further stabilized using DFT calculations. We found the most stable structures in the existing database for all but one composition, even though eight compositions among them were not in the data set trained in a crystal diffusion variational autoencoder. This substantiates the prospect of the generation of an extensive range of compositions. Finally, 205 unique new crystal materials with energy above hull <100 meV/atom were generated. Moreover, we compared the average formation energy of the crystals generated from five compositions, two of which were hypothetical, with that of traditional methods like atom substitution and a generative model. The generated structures had lower formation energy than those of other models, except for one composition. These results demonstrate that our approach can be applied stably in various fields to design stable inorganic materials based on machine learning.


Assuntos
Aprendizado Profundo , Bases de Dados Factuais , Teoria da Densidade Funcional , Difusão , Aprendizado de Máquina
16.
Indian J Plast Surg ; 56(4): 310-319, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-37705815

RESUMO

Introduction The aim of this study was to explore the outcomes of composite grafts in fingertip amputations in children as well as the contributing factors that may affect outcomes. Methods Literature search was conducted across six databases in March 2022 to select studies on the use of composite grafts on fingertip amputations in the pediatric population. Results Twelve articles with 735 composite grafts were identified for review. Most fingertip injuries occurred in the less than 5-year age group and were due to crush type injuries. In studies that reported "complete" graft take as a separate outcome measure, 17.3% of fingertips with this result were observed. In the studies that reported "complete" and "partial" graft take together as an outcome measure, 81.6% of fingertips achieved this outcome. A lower proportion of failed graft take was observed in more distal fingertip amputations. Infection (3.8%) and nail abnormalities (3.4%) were the most common complications following composite grafting. Conclusion Composite grafting can be considered as a useful method of treatment in this population. Clinicians should be aware of the potential complications following this method of treatment such as infection and nail abnormalities. More proximal fingertip amputations may warrant other surgical interventions (beyond Level II on the modified Ishikawa/Ishikawa classification). Significant heterogeneity was observed within the studies, mainly due to lack of standardization in assessment and reporting of outcomes.

17.
Environ Sci Pollut Res Int ; 30(50): 109810-109824, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37777705

RESUMO

Oyster aquaculture has progressively increased to meet growing demands for seafood worldwide; however, its effects on methylmercury (MeHg) production in sediment and accumulation in oysters are largely unknown. In this study, total Hg (THg) and MeHg in sediments collected from aquaculture and reference sites and in farmed and wild oysters were measured and compared to explore potential factors that regulate MeHg production and bioaccumulation at the aquaculture sites. The results showed that the mean concentrations of THg and MeHg in varying sediment depths at the aquaculture site were 34 ± 4.1 ng g-1 and 16 ± 12 pg g-1, respectively. In comparison, the mean concentrations of THg and MeHg in sediments at the reference site were 25 ± 2.5 ng g-1 and 63 ± 28 pg g-1, respectively. While the MeHg/THg in the aquaculture sediments increased with organic carbon content, the slope of MeHg/THg versus organic carbon content was suppressed by high concentrations of dissolved sulfide in the pore water. Multiple parameters (total sulfur, total nitrogen and acid volatile sulfide in sediment, and dissolved sulfide in pore water) showed significant negative relationships with MeHg/THg in the sediment, and the total sulfur content in the sediment showed the highest inverse correlation factor with MeHg/THg (r = - 0.83). The mean concentrations of THg and MeHg in farmed oysters (mean weight 3.2 ± 1.5 g) were 36 ± 10 ng g-1 and 15 ± 6.7 ng g-1, respectively, while those in wild oysters (mean weight 0.92 ± 0.32 g) were 47 ± 9.9 ng g-1 and 15 ± 6.7 ng g-1, respectively. Concerning oysters of the same size range, THg and MeHg levels were higher in farmed oysters than in wild oysters despite the faster growth rate of farmed oysters, suggesting that the Hg content of food sources is more important than growth dilution rates in the control of Hg levels. The mean hazardous quotient for MeHg in farmed oyster was calculated as 0.044 ± 0.020, suggesting no expected health risk from farmed oyster consumption.


Assuntos
Mercúrio , Compostos de Metilmercúrio , Ostreidae , Poluentes Químicos da Água , Animais , Mercúrio/análise , Poluentes Químicos da Água/análise , Monitoramento Ambiental/métodos , Água , Enxofre , Carbono , Sulfetos , Sedimentos Geológicos
18.
Environ Res ; 237(Pt 1): 116888, 2023 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-37586452

RESUMO

Metal contamination and other geochemical alterations affect microbial composition and functional activities, disturbing natural biogeochemical cycles. Therefore, it is essential to understand the influences of multi-metal and geochemical interactions on microbial communities. This work investigated the distributions of total mercury (THg), methylmercury (MeHg), and trace metals in the anthropogenically affected sediment. The microbial communities and functional genes profiles were further determined to explore their association with Hg-methylation and geochemical features. The levels of THg and MeHg in sediment cores ranged between 10 and 40 mg/kg and 0.01-0.16 mg/kg, respectively, with an increasing trend toward bottom horizons. The major metals present at all depths were Al, Fe, Mn, and Zn. The enrichment and contamination indices confirmed that the trace metals were highly enriched in the anthropogenically affected sediment. Various functional genes were detected in all strata, indicating the presence of active microbial metabolic processes. The microbial community profiles revealed that the phyla Proteobacteria, Bacteroidetes, Bathyarchaeota, and Euryarchaeota, and the genera Thauera, Woeseia, Methanomethylovorans, and Methanosarcina were the dominant microbes. Correlating major taxa with geochemical variables inferred that sediment geochemistry substantially affects microbial community and biogeochemical cycles. Furthermore, archaeal methanogens and the bacterial phyla Chloroflexi and Firmicutes may play crucial roles in enhancing MeHg levels. Overall, these findings shed new light on the microbial communities potentially involved in Hg-methylation process and other biogeochemical cycles.

19.
J Hazard Mater ; 459: 132055, 2023 10 05.
Artigo em Inglês | MEDLINE | ID: mdl-37480609

RESUMO

Given their worldwide distribution and toxicity to aquatic organisms, methylmercury (MeHg) and microplastics (MP) are major pollutants in marine ecosystems. Although they commonly co-exist in the ocean, information on their toxicological interactions is limited. Therefore, to understand the toxicological interactions between MeHg and MP (6-µm polystyrene), we investigated the bioaccumulation of MeHg, its cytotoxicity, and transcriptomic modulation in the brackish water flea Diaphanosoma celebensis following single and combined exposure to MeHg and MP. After single exposure to MeHg for 48-h, D. celebensis showed high Hg accumulation (34.83 ± 0.40 µg/g dw biota) and cytotoxicity, which was reduced upon co-exposure to MP. After transcriptomic analysis, 2, 253, and 159 differentially expressed genes were detected in the groups exposed to MP, MeHg, and MeHg+MP, respectively. Genes related to metabolic pathways and the immune system were significantly affected after MeHg exposure, but the effect of MeHg on these pathways was alleviated by MP co-exposure. However, MeHg and MP exhibited synergistic effects on the expression of gene related to DNA replication. These findings suggest that MP can reduce the toxicity of MeHg but that their toxicological interactions differ depending on the molecular pathway.


Assuntos
Cladocera , Mercúrio , Compostos de Metilmercúrio , Sifonápteros , Animais , Compostos de Metilmercúrio/toxicidade , Bioacumulação , Poliestirenos/toxicidade , Microesferas , Transcriptoma , Ecossistema , Plásticos , Microplásticos
20.
Forensic Sci Int ; 350: 111780, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37515918

RESUMO

Marine biofouling occurs when microorganisms, plants, algae, or animals gather on any surface of a man-made object or natural structure. Biofouling organisms are important components of marine ecosystems and vary seasonally and regionally, with environmental factors such as temperature, amount of light, and nutrient availability. Since marine organisms have unique growth patterns, they can be used in marine forensic investigations to estimate time and environment. As few such studies have been done, this study analyzed the growth rates of Balanus on 100 × 100 mm panels of PVC, stainless steel, wood, and cloth and compared these with environmental factors such as temperature. Sets of panels were immersed in Sokcho Harbor, South Korea, each month, and observed monthly after immersion using American Society for Testing and Materials methods. The Balanus on the test panels grew to 1-20 mm and showed different growth patterns depending on when the panels were first immersed.


Assuntos
Incrustação Biológica , Thoracica , Animais , Ecossistema , República da Coreia
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