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1.
Plants (Basel) ; 13(6)2024 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-38592953

RESUMO

The suitable habitat of endangered Ephedra species has been severely threatened and affected by climate change and anthropogenic activities; however, their migration trends and restoration strategies are still relatively understudied. In this study, we utilized the MaxEnt model to simulate the suitable habitats of five endangered Ephedra species in China under current and future climate scenarios. Additionally, we identified significant ecological corridors by incorporating the minimum cumulative resistance (MCR) model. Under the current climate scenario, the suitable area of Ephedra equisetina Bunge, Ephedra intermedia Schrenk ex Mey, Ephedra sinica Stapf, and Ephedra monosperma Gmel ex Mey comprised 16% of the area in China, while Ephedra rhytidosperma Pachom comprised only 0.05%. The distribution patterns of these five Ephedra species were primarily influenced by altitude, salinity, temperature, and precipitation. Under future climate scenarios, the suitable areas of E. equisetina, E. intermedia, and E. sinica are projected to expand, while that of E. monosperma is expected to contract. Notably, E. rhytidosperma will lose its suitable area in the future. Our identified ecological corridors showed that the first-level corridors encompassed a wider geographical expanse, incorporating E. equisetina, E. intermedia, E. sinica, and E. monosperma, while that of E. rhytidosperma exhibited a shorter length and covered fewer geographical areas. Overall, our study provides novel insights into identifying priority protected areas and protection strategies targeting endangered Ephedra species.

2.
ACS Appl Mater Interfaces ; 16(6): 6998-7013, 2024 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-38294419

RESUMO

The rational design and construction of composite electrodes are crucial for overcoming the issues of poor working stability and slow ionic electron mobility of a single component. Nevertheless, it is a big challenge to construct core-shell heterostructures with crystalline/amorphous/crystalline heterointerfaces in straightforward and efficient methods. Here, we have successfully converted a portion of crystalline CoGa2O4 into the amorphous phase by employing a facile sulfidation process (denoted as CoGa2O4-S), followed by anchoring crystalline NiCo-layered double hydroxide (denoted as NiCo-LDH) nanoarrays onto hexagonal plates and nucleation points of CoGa2O4-S, synthesizing dual-type hexagonal and flower-like 3D CoGa2O4-S@NiCo-LDH core-shell heterostructures with crystalline/amorphous/crystalline heterointerfaces on carbon cloth. Furthermore, we further adjust the Ni/Co ratio in LDH, achieving precise and controllable core-shell heterostructures. Benefiting from the abundant crystalline/amorphous/crystalline heterointerfaces and synergistic effect among various components, the CoGa2O4-S@Ni2Co1-LDH electrode exhibits a specific capacity of 247.8 mAh·g-1 at 1 A·g-1 and good rate performance. A CoGa2O4-S@Ni2Co1-LDH//AC flexible asymmetric supercapacitor provides an energy density of 58.2 Wh·kg-1 at a power density of 850 W·kg-1 and exhibits an impressive capacitance retention of 105.7% after 10,000 cycles at 10 A·g-1. Our research provides profound insights into the design of other similar core-shell heterostructures.

3.
Environ Sci Ecotechnol ; 20: 100340, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38162402

RESUMO

Microplastics (MPs), recognized as an emerging global environmental concern, have been extensively detected worldwide, with specific attention directed towards the Yangtze River Estuary (YRE) and East China Sea (ECS) regions. Despite their critical research significance, there remains a knowledge gap concerning the distribution of MPs in the benthic layer within this area, particularly regarding interactions governing their occurrence. Here we illuminate the distribution of MPs within the benthic layer and unravel the intricate interplay between bottom water and sediment in the YRE and ECS. We find that MPs are notably more abundant in bottom water, ranging from 8 to 175 times higher than in surface water. These MPs predominantly consist of polyester fibers, exhibit a size range between 0.5 and 5.0 mm, and display distinct coloration. Co-occurrence network analysis and Principal Coordinate Analysis confirm a robust correlation between MPs in bottom water and sediment, signifying the pivotal role of bottom water in mediating the distribution and transportation of MPs within the benthic layer. Furthermore, a positive correlation between MPs in sediment and bottom water turbidity underscores the impact of surface sediment resuspension and upwelling on MPs distribution. This study clarifies the intricate interactions within the benthic layer and highlights the crucial role of bottom water as a mediator in the vertical distribution of MPs, advancing our understanding of the "source-to-sink" transport processes governing MPs within water-sediment systems.

4.
Water Res ; 235: 119933, 2023 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-37023644

RESUMO

Fiber, the most prevalent plastic type, can be weathered and eroded easily in the natural environment. Although a variety of techniques have been applied to characterize the aging characteristics of plastics, a comprehensive understanding was critically essential to correlate the multi-dimensional assessment of the weathering process of microfibers and their environmental behavior. Therefore, in this study, microfibers were prepared from the face masks and Pb2+ was selected as a typical metal pollutant. The weathering process was simulated by xenon aging and chemical aging, and then subjected to Pb2+adsorption to examine the effect of weathering processes. The changes in fiber property and structure were detected by using various characterization techniques, with the development of several aging indices to quantify the changes. The two-dimensional Fourier transform infrared correlation spectroscopy analysis (2D-FTIR-COS) and Raman mapping were also performed to understand the order of changes in the surface functional groups of the fiber. The results showed that both aging processes altered the surface morphology, physicochemical properties, and polypropylene chain conformations of the microfibers, with stronger effect after chemical aging. The aging process also enhanced the affinity of microfiber to Pb2+. Moreover, the changes and correlation of the aging indices were analyzed, showing that the maximum adsorption capacity (Qmax) was positively related to carbonyl index (CI), oxygen-to-carbon atom (O/C) ratio and intensity ratio of the Raman peaks (I841/808), but negatively related to contact angle and the temperature at the maximum weight loss rate (Tm). The O/C ratio was more suitable to quantify the surface changes with lower aging degree while the CI value explained the chemical aging process better. Overall, this study discussed the weathering processes of microfibers based on a multi-dimensional investigation, and attempted to correlate the aging characteristics of the microfibers and their environmental behavior.


Assuntos
Poluentes Ambientais , Poluentes Químicos da Água , Chumbo , Plásticos , Polipropilenos , Temperatura , Poluentes Ambientais/análise , Poluentes Químicos da Água/química
5.
Sci Total Environ ; 859(Pt 1): 160227, 2023 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-36400290

RESUMO

The coexistence of minerals, heavy metals and microplastics in sediment has been widely reported, while the interactions between minerals and heavy metals may be affected by the presence of microplastics. Therefore, to elucidate the effect of microplastics on the interactions between heavy metals and sediment minerals, this study conducted a series of experiments using polystyrene (PS) microplastics, Pb/Cr/Cd and ferrihydrite (Fh). The presence of PS microplastics with ferrihydrite (Fh-MPs200, mass ratio of ferrihydrite to PS of 200:1) improved the adsorption capacity of ferrihydrite, especially with an increase of 36 % for Pb. Morphological characterization demonstrated that the nano-ferrihydrite particles were dispersed on the surface of the PS microplastics, increasing the available reaction sites of the ferrihydrite particles. Furthermore, the results of zeta potential and pH effect showed that the reduction in electrostatic repulsion after adding PS was another critical reason for the increase in Pb adsorption by Fh-MP200. As a result, the presence of PS microplastics enhanced the complexation of Pb ions and the hydroxyl groups on the ferrihydrite surface. This study demonstrated that the presence of microplastics in the sedimentary environment can alter the dispersion and surface properties of minerals, thereby affecting the accumulation and transportation of heavy metals at the water-sediment interface.


Assuntos
Metais Pesados , Poluentes Químicos da Água , Microplásticos/química , Plásticos/química , Poluentes Químicos da Água/análise , Metais Pesados/química , Adsorção , Minerais , Poliestirenos
6.
BMC Nephrol ; 23(1): 234, 2022 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-35778681

RESUMO

BACKGROUND: The all-cause mortality of patients undergoing hemodialysis (HD) is higher than in the general population. The first 6 months after dialysis are important for new patients. The aim of this study was to develop and validate a nomogram for predicting the 6-month survival rate of HD patients. METHODS: A prediction model was constructed using a training cohort of 679 HD patients. Multivariate Cox regression analyses were performed to identify predictive factors. The identified factors were used to establish a nomogram. The performance of the nomogram was assessed using the C-index and calibration plots. The nomogram was validated by performing discrimination and calibration tests on an additional cohort of 173 HD patients. RESULTS: During a follow-up period of six months, 47 and 16 deaths occurred in the training cohort and validation cohort, respectively, representing a mortality rate of 7.3% and 9.2%, respectively. The nomogram comprised five commonly available predictors: age, temporary dialysis catheter, intradialytic hypotension, use of ACEi or ARB, and use of loop diuretics. The nomogram showed good discrimination in the training cohort [C-index 0.775(0.693-0.857)] and validation cohort [C-index 0.758(0.677-0.836)], as well as good calibration, indicating that the performance of the nomogram was good. The total score point was then divided into two risk classifications: low risk (0-90 points) and high risk (≥ 91 points). Further analysis showed that all-cause mortality was significantly different between the high-risk group and the low-risk group. CONCLUSIONS: The constructed nomogram accurately predicted the 6-month survival rate of HD patients, and thus it can be used in clinical decision-making.


Assuntos
Antagonistas de Receptores de Angiotensina , Nomogramas , Inibidores da Enzima Conversora de Angiotensina , Humanos , Diálise Renal , Taxa de Sobrevida
7.
Mar Pollut Bull ; 181: 113940, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35853409

RESUMO

Microplastics (MPs) are widely present in global oceans, and can pose a threat to marine organisms. This study examined the abundance and characteristics of MPs in seawater, sediment, and organism samples collected from Hangzhou Bay. Abundance of MPs in seawater (n = 26) and sediment (n = 26) were 0.77-9.6 items/m3 and 44-208 items/kg dw, respectively. Size of MPs in sediment (mean 2.5 mm, range 0.21-5.3 mm) was significantly (p < 0.05) larger than that in seawater (1.1 mm, 0.13-4.9 mm). Fiber was consistently the predominant shape of MPs in seawater and sediment. The major polymer composition of MPs was polyethylene (PE; mean 47 %) in seawater, but textile cellulose (60 %) was the main polymer type of MPs in sediment. Average abundance of MPs in marine organisms (n = 388) ranged from 0.064 (zooplankton) to 2.9 (Harpodon nehereus) items/ind, with the mean size of 0.19-1.4 mm. MP abundance in marine organisms was not significantly correlated with their trophic level. Fiber was always the predominant shape of MPs in different marine organisms, contributing mean 67 (fish)-93 % (zooplankton) of total MPs. MPs in crustacean (mean 58 %), shellfish (64 %), and cephalopod (29 %) were dominated by textile cellulose. Whereas, PE (mean 44 %) and polypropylene (43 %) were the major polymer compositions of MPs in fish and zooplankton, respectively. To our knowledge, this is the most comprehensive study investigating the occurrence of MPs in environmental matrixes from Hangzhou Bay, which contributes to the better understanding of environmental behaviors of MPs in estuarine sea environment.


Assuntos
Microplásticos , Poluentes Químicos da Água , Animais , Organismos Aquáticos , Baías , Celulose , Monitoramento Ambiental , Peixes , Plásticos , Água do Mar , Poluentes Químicos da Água/análise , Zooplâncton
8.
J Colloid Interface Sci ; 619: 106-115, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35378472

RESUMO

The inferior conductivity and infamous "shuttle effect" of lithium-sulfur (Li-S) batteries lead to low sulfur utilization and undesired cycle stability, which both seriously affect their practical application. Here, a multifunctional nanofiber material based on cerium dioxide spheres embedded inside nitrogen-doped carbon fibers (denoted as NCF@CeO2) fabricated by electrospinning technology is used as an interlayer for high-performance Li-S batteries. The nitrogen-doped carbon fiber skeleton matrix provides a through-conducting grid to accelerate electron transfer at the interface of the nitrogen-doped carbon and the CeO2, and the large specific surface area guarantees a sufficient interfacial fast-redox reaction for sulfur species. CeO2 with a hollow structure provides strong physicochemical adsorption of lithium polysulfides (LiPSs) to weaken the migration behavior, and abundant oxygen defects as catalytic active sites are conducive to lithium sulfide conversion. The "sphere in fiber" construction minimizes the direct contact between the catalyst and electrolyte, effectively avoiding side reactions. Based on the multiple functions of nitrogen-doped carbon fibers and CeO2, Li-S batteries with NCF@CeO2 interlayers exhibit superior electrochemical performances, including a high discharge specific capacity of 1072.9 mAh g-1 at 0.2 C and a low capacity decay rate of only 0.063% per cycle after 1000 cycles. Moreover, the mechanisms of LiPSs adsorption-conversion and the quantification of the catalytic ability are elaborately clarified.

9.
Nat Prod Res ; 36(2): 578-585, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32666830

RESUMO

In the course of our efforts to search new secondary metabolites from marine-derived fungi, one new hexylitaconic acid derivative, 3-(5-methoxycarbonylpentyl)-4-methylfuran-2,5-dione (1), and two dimeric analogues asperwelwinates A and B (2 and 3), together with ten known compounds, asperitaconic acid C (4), kotanin (5) and orlandin (6), desertorin B (7), fonsecinone A (8), aurasperone A (9), asperpyrones B and C (10 and 11), aspernigrin B (12), and pyrophen (13), were isolated from a strain of Aspergillus welwitschiae CUGBMF180262. The structures of compounds 1-3 were determined by detailed analysis of HRMS, and 1D/2D NMR experiments, while the absolute configurations of 2 and 3 were determined by comparison of experimental and calculated electronic circular dichroism spectra. 2 and 3 were first reported dimeric hexylitaconic acid derivatives. Compounds 8, 9 and 11 showed moderate antibacterial activities against Helicobacter pylori with minimum inhibitory concentration (MIC) values of 16 µg/mL.


Assuntos
Aspergillus , Fungos , Antibacterianos/farmacologia , Testes de Sensibilidade Microbiana , Estrutura Molecular , Succinatos
10.
Sci Total Environ ; 806(Pt 2): 150458, 2022 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-34592275

RESUMO

While mechanical abrasion by water and sediment is a primary and critical step in weathering process, the upsurge of discarded face masks will undoubtedly become a potential source of micro-/nanofibers owing to the spread of novel coronavirus (COVID-19) pneumonia. However, effects of mechanical abrasion on discarded face masks have neither been seriously addressed nor understood. Therefore, we conducted a simulated experiment to explore abundance, size distribution and morphology of microfibers released from common, surgical and face filtering piece (FFP) masks after mechanical abrasion. Technologies such as Fourier transform infrared spectrometry, fluorescence microscopy, scanning electron microscopy, and confocal laser scanning microscopy were used. Results showed that the abundance of released microfibers followed order of surgical > common > FFP in both water and sediment environments, and the maximum abundance reached 272 ± 12.49 items per square centimeter of mask (items·cm-2) after sediment abrasion. Taking surgical mask for further investigation, the length of released fiber was observed to vary from 47.78 µm to 3.93 mm, and 72.41-89.58% of the total number of released microfibers fell in the range of 0.1-1 mm. However, microfibers with a very small length (1-100 µm) can occupy 0.09-13.59% of the total number of released fibers in sediment environment. The roughness of fiber surface after sediment abrasion was successively increased. Furthermore, the morphology analysis showed significant changes with countless cracks and many prominent protrusions on fiber surface after sediment abrasion. The cracks and protrusions may further accelerate mask decomposition, thereby potentially resulting in the adsorption of other contaminants and the release of self-containing chemicals. This study provides a valuable database of microfibers released from discarded face masks at the primary but critical stage, and further contributes knowledge on environmental impact of discarded personal protective equipment due to COVID-19.


Assuntos
COVID-19 , Máscaras , Humanos , Equipamento de Proteção Individual , SARS-CoV-2 , Tempo (Meteorologia)
11.
Environ Sci Pollut Res Int ; 29(8): 11966-11975, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34558049

RESUMO

To enhance the remediation efficiency of arsenic (As) and chromium (Cr)co-contaminated soil, the effect of various combinations of reducing and chelating agents on the removal of As and Cr was studied in the present work by using electrokinetic technology coupled with a permeable reactive barrier (EK-PRB). In an experiment with EK-PRB, reducing agents (ascorbic acid and citric acid) and chelating agents (EDTA-2Na) were applied together with CaAl-layered double hydroxide (CaAl-LDH) to pretreat As and Cr co-contaminated soil. The chelating agents increased the removal efficiency of As and Cr, while the reducing agent only improved As removal in co-contaminated soil. The best removal efficiencies of As and Cr were 41.2% and 46.8%, respectively. The reducing agents promoted the production of As(III) and enhanced the migration of As. However, a large amount of Cr(VI) was reduced to Cr(III), which affected the migration of Cr. Although the addition of chelating agents partly increased the migration of Cr(III), the removal of total chromium (TCr) still decreased. In this remediation system, a PRB can effectively capture and fix As and Cr. The results indicated that As was mainly adsorbed on the surface of CaAl-LDH, while the surface adsorption and intercalation of CaAl-LDH were the main mechanisms for Cr.


Assuntos
Arsênio , Recuperação e Remediação Ambiental , Poluentes do Solo , Cromo/análise , Cinética , Solo , Poluentes do Solo/análise
12.
Water Res ; 204: 117580, 2021 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-34469810

RESUMO

The increasing microplastic pollution together with the plastisphere-associated ecological threats in coastal areas have aroused global concern. Tropical cyclones have been increased in both frequency and intensity under global warming, causing intense impact on the microplastics distribution and the structure of coastal ecosystems. However, until most currently, the extent to which typhoon impacts the microplastics and plastisphere community remains poorly known. This study analyzed the effects of Typhoon Wipha (Code: 1907) on microplastics abundance and composition in surface water and sediment crossed coastal areas of Shenzhen. Here we found a significant typhoon-induced increase in microplastics abundance in surface water, whereas an opposite trend was observed in sediment. Despite the evident transportation of microplastics from sediment to surface water by agitation, a possible microplastics influx was introduced by typhoon as evidenced by the large attribution of unknown force in source tracking analysis. Furthermore, typhoon had adeptly uniformed the plastisphere community in the sediment along the 190 km costal line overnight. A significant increase of nitrogen fixer, Bradyrhizobiaceae, was observed ubiquitously after typhoon, which might alter the nitrogen cycling and increase eutrophic condition of the coastal ecological system. Together, this study expanded the knowledge about the impact of typhoon-induced influx of the microplastics on coastal biogeochemical cycling. Moreover, the microplastics and the plastisphere compositional pattern revealed here will underpin future studies on adsorption behavior, interfacial processes and ecotoxicity of the coastal microplastic pollution.


Assuntos
Tempestades Ciclônicas , Poluentes Químicos da Água , Ecossistema , Monitoramento Ambiental , Poluição Ambiental , Microplásticos , Plásticos
13.
Mar Drugs ; 19(6)2021 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-34071288

RESUMO

Nine new secondary metabolites, including six isocoumarin analogues, 7-hydroxyoospolactone (1), 7-methoxyoospolactone (2), 7-methoxy-9-hydroxyoospolactone (3), 10-acetoxy-9-hydroxyoospolactone (4), 6-dehydroxysescandelin (5), parapholactone (6), and three compounds with a rare skeleton of isocoumarin coupled with phenylethylamine, namely paraphamide A (12), paraphamide B (13), and paraphamide C (14), together with five known compounds, oospolactone (7), 8-O-methyloospolactone (8), 10-hydroxyoospolactone (9), 9,10-dihydroxyoospolactone (10), and oospoglycol (11), were isolated and identified from the marine-derived fungus Paraphoma sp. CUGBMF180003. Their chemical structures were determined using spectroscopic data, including HRESIMS and 1D and 2D NMR techniques. Furthermore, the stereogenic carbons in 5 and 14 were determined by comparing the experimental and calculated electronic circular dichroism (ECD) spectra. The carbon skeleton of 12-14 was identified as the first example of isocoumarin coupled with phenylethylamine derivatives. All of these compounds were examined for antimicrobial activities against Candida albicans and Staphylococcus aureus. Both 1 and 6 showed antibacterial activity against S. aureus with MIC values of 12.5 µg/mL.


Assuntos
Anti-Infecciosos , Ascomicetos/metabolismo , Isocumarinas , Anti-Infecciosos/química , Anti-Infecciosos/isolamento & purificação , Anti-Infecciosos/farmacologia , Candida albicans/efeitos dos fármacos , Candida albicans/crescimento & desenvolvimento , Fermentação , Isocumarinas/química , Isocumarinas/isolamento & purificação , Isocumarinas/farmacologia , Testes de Sensibilidade Microbiana , Estrutura Molecular , Metabolismo Secundário , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/crescimento & desenvolvimento
14.
Antibiotics (Basel) ; 10(4)2021 Apr 03.
Artigo em Inglês | MEDLINE | ID: mdl-33916658

RESUMO

Four new secondary metabolites, including one spiro[anthracenone-xanthene] derivative aspergiloxathene A (1), one penicillide analogue, Δ2'-1'-dehydropenicillide (2), and two new phthalide derivatives, 5-methyl-3-methoxyepicoccone (3) and 7-carboxy-4-hydroxy-6-methoxy-5-methylphthalide (4), together with four known compounds, yicathin C (5), dehydropenicillide (6), 3-methoxyepicoccone (7), 4-hydroxy-6-methoxy-5-methylphthalide (8), were identified from the marine-derived fungus Aspergillus sp. IMCASMF180035. Their structures were determined by spectroscopic data, including high-resolution electrospray ionization mass spectrometry (HRESIMS), 1D and 2D nuclear magnetic resonance (NMR) techniques. Compound 1 was identified as the first jointed molecule by xanthene and anthracenone moieties possessing an unprecedented carbon skeleton with spiro-ring system. All compounds were evaluated activities against Staphylococcus aureus, methicillin resistant S. aureus (MRSA), Escherichia coli, Escherichia faecium, Pseudomonas aeruginosa, and Helicobacter pylori. Compound 1 showed significant inhibitory effects against S. aureus and MRSA, with minimum inhibitory concentration (MIC) values of 5.60 and 22.40 µM. Compounds 2 and 6 exhibited potent antibacterial activities against H. pylori, with MIC values of 21.73 and 21.61 µM, respectively.

15.
J Colloid Interface Sci ; 589: 208-216, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33460852

RESUMO

Lithium-sulfur batteries have attracted numerous attentions owing to their high theory discharge specific capacity and energy density. However, sulfur cathode usually suffers from poor cycle stability and slow reaction kinetics, caused by its poor conductivity, excessive volume changes during charge/discharge processes, complex sulfur species conversion reaction and the dissolution of polysulfide intermediates. Here, we present a free-standing framework of Mn3O4 nanoparticles combine with polypyrrole (PPy) nanotubes as host materials for lithium-sulfur batteries to overcome these issues. In this construction, PPy nanotubes serve as the excellent container of sulfur and physical barrier for the excessive volume expansion of sulfur during electrochemical reaction processes, and the nanotubes also provide an efficient conductive network for the rapid transmission of electrons and ions, while Mn3O4 nanoparticles facilitate trapping lithium polysulfides. The coordination of PPy nanotubes and Mn3O4 effectively alleviate the shuttle effect as well as enhance the utilization of sulfur. The obtained PPy@Mn3O4-S sample shows high capacities of 1419.9 and 925.5 mAh g-1 at 0.1 C and 1 C rate, respectively, and exhibits a low capacity fading rate of 0.062% per cycle for 800 cycles at 1 C rate. This work provides a new and effective way for the design of lithium-sulfur batteries with both high rate performance and long cycle stability.

16.
Anal Chem ; 92(21): 14346-14356, 2020 11 03.
Artigo em Inglês | MEDLINE | ID: mdl-32880171

RESUMO

Micro(nano)plastics (MNPs) are widely acknowledged as global environmental threat while determination methods for MNPs are still lacking and becoming a growing concern. This study provides a novel method for MNPs identification/quantification by matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI-TOF MS). Factors affecting the measurement were optimized, including laser energy, matrix (M), analyte (A), cationization agent (C), and MAC volume ratio. Under the optimal conditions, the peaks representative of polystyrene (PS) and polyethylene terephthalate (PET) were identified, and the mass differences were consistent with the molecular weight of the corresponding oligomer. A quantitative correlation was built between normalized signal intensity and ln[polymer concentration] with a correlation coefficient above 0.96 for low-molecular-weight polymers and 0.98 for high-molecular-weight polymers. Furthermore, two types of environmental MNP samples were prepared, including aviation cup particles as fresh plastics and aged MNPs extracted from river sediment. By using MALDI-TOF MS, the PS-related MNPs (in both aviation cup and sediment) consisted of C8H8 and C16H16O oligomers, while the PET-related MNPs (only found in sediment) were identified with repeated units of C10H8O4 and C12H12O4. According to the quantitative correlation curve, the contents of PS and PET MNPs were quantified as 8.56 ± 0.04 and 28.71 ± 0.20 mg·kg-1, respectively, in the collected sediment. This study is the first attempt to propose a quantification method with the employment of MALDI-TOF MS for aged MNPs analysis in environmental samples, which can not only supply an effective method for MNP analysis but also inspire future studies on the in situ distribution and transformation of MNPs in environmental and biological samples.


Assuntos
Meio Ambiente , Microesferas , Nanopartículas/química , Plásticos/análise , Plásticos/química , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/métodos , Peso Molecular , Polietilenotereftalatos/química , Poliestirenos/química
17.
Medicine (Baltimore) ; 99(17): e19783, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32332621

RESUMO

INTRODUCTION: Solitary fibrous tumor (SFT) is an uncommon mesenchymal tumor that is most common in the pleura. However, according to previous studies, the SFT of the pancreas is extremely rare; only 20 cases have been reported so far. Here, we conduct a literature review and report the first case of atypical/malignant SFT of the pancreas with spleen vein invasion. PATIENT CONCERNS: The patient is a 61-year-old Chinese male who presented with 1 week of upper abdominal pain. Abdominal magnetic resonance imaging showed a huge mass (>10 cm) at the distal end of the pancreas, and the mass obstructing the splenic vein. DIAGNOSIS: Atypical/malignant SFT of the pancreas with splenic vein tumor thrombus. INTERVENTIONS: The patient underwent laparoscopic distal pancreatectomy with splenectomy procedure to achieve a radical resection, and did not undergo chemotherapy or radiotherapy. OUTCOMES: Abdominal computed tomography scans were performed at 1 and 4 months after resection, and no signs of recurrence or metastasis were found (. B).(Figure is included in full-text article.) CONCLUSION:: The clinical symptoms of atypical/malignant SFT of the pancreas with spleen vein invasion are not atypical, and imaging feature is lack of specificity. Preoperative diagnosis is difficult, and there is a potential for malignancy. However, due to the paucity of randomized control trials, there is no established, globally accepted treatment strategy, radiation therapy and chemotherapy regimens have not demonstrated global effectiveness, and no standardized treatments have been identified. Therefore, we recommend complete surgical resection and close clinical follow-up.


Assuntos
Pâncreas/anormalidades , Tumores Fibrosos Solitários/diagnóstico , Veia Esplênica/anormalidades , Humanos , Laparoscopia/métodos , Masculino , Pessoa de Meia-Idade , Pâncreas/fisiopatologia , Pâncreas/cirurgia , Tumores Fibrosos Solitários/diagnóstico por imagem , Tumores Fibrosos Solitários/cirurgia , Veia Esplênica/fisiopatologia , Veia Esplênica/cirurgia , Tomografia Computadorizada por Raios X/métodos
18.
Chemosphere ; 241: 125038, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31610455

RESUMO

The use of humic acid (HA) and fulvic acid (FA) as reinforcing agents to improve the efficiency of electrokinetic remediation (EKR) were investigated for the first time using an artificially contaminated soil. A series of soil leaching tests and bench-scale EKR experiments were performed to elucidate the mechanisms of As removed from artificially contaminated soil. The characterization of total reducing capacity (TRC) and functional group were carried out to reveal the difference of HA and FA. The observations demonstrated that with 0.1 M NaOH and KCl as the anolyte, using both HA and FA enhanced the efficiency of EKR. After 25 days of EKR, the removal efficiency of TAs in HA/FA-enhanced EKR was about 2.0-3.0 times greater than when unenhanced. Compared to HA, more As was removed in EKR with FA, which has more TRC and oxygen-containing groups. These EKR experimental results, with the support of data obtained from soil leaching test, indicate that competitive adsorption, reductive dissolution and complexation were the reasons why HA and FA promoted the release of As in the soil and further enhanced the remediation efficiency.


Assuntos
Arsênio/isolamento & purificação , Benzopiranos/farmacologia , Técnicas Eletroquímicas/métodos , Recuperação e Remediação Ambiental/métodos , Substâncias Húmicas/análise , Poluentes do Solo/isolamento & purificação , Adsorção , Poluentes do Solo/análise , Temperatura
19.
Front Chem ; 8: 633949, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33520945

RESUMO

Na2Fe0.6Mn0.4PO4F/C composite materials are synthesized with various carbon sources via a simple spray-drying method in this study, and the effect of carbon sources on structure, morphology, and electrochemical properties of Na2Fe0.6Mn0.4PO4F/C materials are investigated in detail. XRD and SEM results indicate that the reduction ability of carbon sources has a key impact on the structure and morphology of Na2Fe0.6Mn0.4PO4F/C composite materials. Among these Na2Fe0.6Mn0.4PO4F/C materials, the sample prepared with ascorbic acid presents a uniform hollow spherical architecture. Electrochemical analysis demonstrates that the Na2Fe0.6Mn0.4PO4F/C sample prepared with ascorbic acid has optimal electrochemical performance. The sample shows high discharge capacities of 95.1 and 48.1 mAh g-1 at 0.05C and 1C rates, respectively, and it exhibits an improved cycle stability (91.7% retention after 100 cycles at 0.5C), which are superior to Na2Fe0.6Mn0.4PO4F/C materials prepared with other carbon sources. This study demonstrates that the reduction ability of carbon sources significantly influences the electrochemical properties of fluorophosphate/C composite materials. This work also provides a promising strategy to obtain high performance cathode materials for sodium-ion batteries.

20.
Mar Drugs ; 17(5)2019 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-31091673

RESUMO

Two new spiro-heterocyclic γ-lactam derivatives, cephalimysins M (1) and N (2), were isolated from the fermentation cultures of the marine-derived fungus Aspergillus fumigatus CUGBMF17018. Two known analogues, pseurotin A (3) and FD-838 (4), as well as four previously reported helvolic acid derivatives, 16-O-propionyl-16-O-deacetylhelvolic acid (5), 6-O-propionyl-6-O-deacetylhelvolic acid (6), helvolic acid (7), and 1,2-dihydrohelvolic acid (8) were also identified. One-dimensional (1D), two-dimensional (2D) NMR, HRMS, and circular dichroism spectral analysis characterized the structures of the isolated compounds.


Assuntos
Organismos Aquáticos/química , Aspergillus fumigatus/química , Furanos/química , Imidazóis/química , Lactamas/química , Pirrolidinonas/química , Compostos de Espiro/química , Dicroísmo Circular , Ácido Fusídico/análogos & derivados , Ácido Fusídico/química , Espectroscopia de Ressonância Magnética , Estrutura Molecular
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