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1.
Sci Total Environ ; 802: 149752, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34454148

RESUMO

In present work, the synergistic effects during co-pyrolysis of low-density polyethylene (LDPE) and torrefied Chinese herb residues (CHR) have been investigated by thermogravimetric analysis. The kinetic parameters of co-pyrolysis were calculated by Coats-Redfern method, and the difference values of experiment and theoretical were also investigated for gas and oil compounds. The results show that the extent of synergistic or inhibitory effects of co-pyrolysis was connection with the severity of CHR torrefaction, and the activation energy depend on the blend ratio of LDPE and CHRs. In addition, co-pyrolysis tends to generate more small molecule products and reduce oil yield, and increase the CO content but decreases CH4 in the gas product. The results also found that the liquid products have a significant interaction during the co-pyrolysis process, because the content of aliphatic hydrocarbons and alcohols in the blends pyrolysis oil has been greatly increased, and improving the quality of oil.


Assuntos
Polietileno , Pirólise , Biomassa , China , Temperatura Alta , Cinética
2.
Sci Total Environ ; 802: 149736, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34464809

RESUMO

Microplastics (MPs) have been found in the natural environment and even in the organs of fish, which is attracting worldwide attention. In this study, agricultural film was milled to simulate secondary polyethylene microplastics (PE-MPs) to evaluate their effect and toxicity on the growth, liver damage, and gut microbiome composition of crucian (Carassius carassius), a common freshwater fish, after 30 days of feed exposure. Three fish feed treatments with different PE-MPs concentrations, low, medium, and high, whose PE-MPs intake was 6.38, 12.18, and 22.33 mg MPs/fish/day, respectively, were used. The results indicated that crucian growth was promoted in the low and medium PE-MPs groups due to the increase in Firmicutes and decrease in Bacteroidetes, probably resulting in obesity and lipid accumulation, while the growth rate of crucians in the high PE-MPs group showed a clear downward trend. Severe liver damage was observed in PE-MPs-treated groups. Disordered liver tissue and necrosis of pancreatic acinar epithelial cells were observed in the medium and high PE-MPs groups compared with those of the control group. The gut microbiome composition of crucians showed significant alteration, and some harmful bacteria were found in the gut following PE-MPs exposure. Alpha diversity indices revealed that the diversity of the gut microbiome rose markedly in the low, medium, and high PE-MPs groups. This study suggests that MPs adversely affect crucian growth and health, with increased disease risk.


Assuntos
Carpas , Microbioma Gastrointestinal , Poluentes Químicos da Água , Animais , Fígado/química , Microplásticos , Plásticos/toxicidade , Polietileno/toxicidade , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/toxicidade
3.
Chemosphere ; 287(Pt 3): 132310, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34826948

RESUMO

In this study, a nano-adsorbent was prepared for kerosene removal from water. Multiwalled carbon nanotubes (MWCNTs) were functionalized with concentrated HNO3 (nitric acid). Subsequently, Fe3O4 (magnetite) nanoparticles were deposited on the MWCNTs to prepare a magnetite/MWCNTs (Fe-MWCNTs) nanocomposite. Then, polyethylene was added to the Fe-MWCNTs to fabricate a polyethylene/magnetite/MWCNTs (PE/Fe-MWCNTs) novel nanocomposite. The nano-adsorbent was characterized using BET, FTIR, Raman, XRD, TEM, and SEM. A kerosene-water model mixture was used for adsorption tests. Several parameters: adsorption time, adsorbent dose, solution pH, solution temperature, and kerosene concentration in the kerosene-water model mixture, were analyzed during adsorption experiments. After each batch experiment, kerosene concentration was determined using high-performance liquid chromatography (HPLC). Magnetic field was used to remove the adsorbent after each experiment. The kerosene adsorption capacity and removal efficiency of the PE/Fe-MWCNTs nanocomposite (3560 mg/g and 71.2 %, respectively) were higher than those of Fe-MWCNTs, ox-MWCNTs, and fresh MWCNTs (3154 mg/g and 63.1 %, 2204 mg/g and 44.0 %, and 2092 mg/g and 41.8 %, respectively). Kerosene adsorption followed a pseudo-second-order kinetic model (R2 = 0.999) and the Langmuir isotherm model, suggesting that adsorption was uniform and homogenous process.


Assuntos
Nanotubos de Carbono , Poluentes Químicos da Água , Purificação da Água , Adsorção , Óxido Ferroso-Férrico , Concentração de Íons de Hidrogênio , Querosene , Cinética , Polietileno , Água , Poluentes Químicos da Água/análise
4.
Sci Total Environ ; 806(Pt 1): 150238, 2022 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-34560460

RESUMO

Soil-biodegradable plastic mulch films are a promising alternative to polyethylene mulches, but adoption has been slow, in part because of uncertainties about in-field degradation. The international biodegradability standard EN-17033 requires 90% degradation within 2 years in an aerobic incubation at constant temperature (20-28 °C). However, in-laboratory biodegradability does not guarantee in-field degradation will follow the same timeframe. Field test protocols are needed to assess biodegradable mulches under a range of environmental conditions and collate site-specific information to predict degradation. Our objectives were to (1) monitor in-field degradation of soil-biodegradable plastic mulches following successive applications and incorporations, (2) quantify mulch recovery 2 years after the final incorporation, and (3) compare in-field degradation with the laboratory standard in terms of calendar and thermal times based on a zeroth-order kinetics model. A field experiment was established in spring 2015 in Mount Vernon, WA testing five biodegradable mulches laid each spring and incorporated each fall until 2018. Mulch recovery was quantified every 6 months until fall 2020, 2 years after the final incorporation. While mulches were incorporated annually, recovery of visible fragments (>2.36 mm) was constant or decreasing over time, indicating mulch deterioration kept pace with new additions. In fall 2020, mulch recovery was 4-16% of total mulch mass incorporated. A zeroth-order kinetics model was used to analyze mulch degradation after the final application. Model extrapolations indicate it would take 21 to 58 months to reach 10% recovery (90% degradation), exceeding the laboratory standard's 24-month benchmark by up to a factor of 2.4. However, when the analysis is done with thermal time, better agreement between in-field and laboratory degradation rates is observed. While other factors, including soil type, soil moisture, and mulch fragment size are also at play, thermal time, rather than calendar time, will be more applicable for assessing site-specific, in-field mulch degradation.


Assuntos
Plásticos Biodegradáveis , Solo , Agricultura , Polietileno , Microbiologia do Solo
5.
Chemosphere ; 287(Pt 4): 132357, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34600348

RESUMO

Large amounts of microplastics can accumulate in wastewater treatment plants (WWTPs), and sludge disposal is suspected to be a major source of microplastics pollution in the environment. It is therefore important to investigate the distribution of microplastics in the sludge of each processing unit of WWTPs. However, little information is available on this topic in China. Accordingly, in this study, the abundance and characteristics of microplastics in the sludge of two WWTPs in Chengdu were investigated. The abundance of microplastics in the sludge samples ranged from 44.4 n·kg-1 to 750.0 n·kg-1. Microplastics were mainly divided into particles (32.16%), debris (28.14%) and fibers (17.08%) according to their shape, and the colors of the microplastics were mainly green (35.19%) and translucent (18.06%). The particle sizes were mainly larger than 1 mm in dimension. Polyethylene, polypropylene and polystyrene were the prevalent types of microplastics analyzed. Our results provide basic information for better understanding the characteristics of microplastics in sludge and for improving sludge treatment.


Assuntos
Poluentes Químicos da Água , Purificação da Água , China , Monitoramento Ambiental , Microplásticos , Plásticos , Polietileno , Esgotos , Eliminação de Resíduos Líquidos , Águas Residuárias/análise , Poluentes Químicos da Água/análise
6.
Sci Total Environ ; 804: 150188, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34798736

RESUMO

Microplastics and nanomaterials are applied in a myriad of commercial and industrial applications. When leaked to natural environments, such small particles might threaten living organisms' health, particularly when considering their potential combination that remains poorly investigated. This study investigated the physiological and biochemical effects of polyethylene (PE; 64-125 µm in size, 0.1, 1.0, and 10.0 mg·L-1) single and combined with an engineered nanomaterial applied in antifouling coatings, the copper-aluminium layered double hydroxides (Cu-Al LDH; 0.33, 1.0, and 3.33 mg·L-1) in the flatfish Solea senegalensis larvae (8 dph) after 3 h exposure, in a full factorial design. Particles ingestion, histopathology, and biochemical biomarkers were assessed. Fish larvae presented <1 PE particles in their gut, independently of their concentration in the medium. The histological health index showed minimal pathological alterations at PE combined exposure, with a higher value observed at 1 mg LDH·L-1 × 0.1 mg PE·L-1. Gut deformity and increased antioxidant defences (catalase), neurotransmission (acetylcholinesterase), and aerobic energy production (electron transport system) were observed at PE ≥ 1.0 mg·L-1. No oxidative damage (lipid peroxidation) or alterations in the detoxification capacity (glutathione-S-transferase) was observed on single and combined exposures. PE, combined or not with Cu-Al LDH, does not seem to compromise larvae's homeostasis considering levels reported so far in the marine and aquaculture environments. However, harsh effects are expected with MP contamination rise, as projections suggest.


Assuntos
Linguados , Poluentes Químicos da Água , Acetilcolinesterase , Animais , Microplásticos , Plásticos , Polietileno/toxicidade , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/toxicidade
7.
J Environ Manage ; 301: 113848, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34597950

RESUMO

Biodegradation could be a potential alternative solution to polyethylene (PE) pollution. However, its hydrophobic surface and long carbon chains make extremely low biodegradation efficiency. In this study, we screened a novel potential bacterial strain C5 (CGMCC number: 1.18715) for low-density polyethylene (LDPE) biodegrading from landfills. The strain was identified as Bacillus velezensis according to its 16S rRNA sequence. The contact angle analysis indicated that C5 could rapidly form biofilm on untreated LDPE which resulted in contact angles decreasing from 100° to 54° over 7 d. After the LDPE film incubated with C5 for 90 d, the thickness and weight of LDPE film decreased by 26% and 8.01%, respectively. Besides, the biotreated PE film was found with increases in weight-averaged molecular weight by 29.8%, suggesting low molar mass chains were consumed. C24-C29 n-alkanes were detected in the biodegradation products, which proved the depolymerization of LDPE. Combined with the genome mining results, a possible biofilm-aided degrading mechanism was proposed and might involve key enzymes, such as laccase, cytochrome P450 and propionyl-CoA carboxylase, which could constitute a multienzyme system for the co-catalytic degradation of LDPE waste.


Assuntos
Bacillus , Polietileno , Bacillus/genética , Biodegradação Ambiental , RNA Ribossômico 16S/genética
8.
Sci Total Environ ; 803: 149921, 2022 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-34482135

RESUMO

Plastic pollution poses a global threat to aquatic organisms, yet its effect on many species remains poorly documented and understood. This study addresses the impact caused by different sizes of polyethylene (PE) plastics on the common carp and evaluates their multi-biomarkers response. We investigated the histological structure and measurement of biochemical alterations, antioxidant enzymes, immunological responses, and fluctuations in blood profiles of the organisms after 15 days of exposure to a concentration of 100 mg/L of nano- (NPs), micro- (MPs) and macroplastics (MaPs). The fish health status was altered in the sole presence of PE particles. All biomarkers changed after exposure compared to the control group, with larger changes being observed with the decreasing size of particles (NPs > MPs > MaPs) compared to their absence. A synergistic effect resulting from the individual impact of plastics penetration in the circulatory system, bursting biochemical responses, and lesions in tissues, might explain the more considerable impact of NPs compared to MPs and/or MaPs.


Assuntos
Carpas , Poluentes Químicos da Água , Animais , Biomarcadores , Microplásticos , Plásticos , Polietileno , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/toxicidade
9.
Sci Total Environ ; 803: 149887, 2022 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-34487899

RESUMO

Microplastics (MPs) in marine environments have raised increasing concerns worldwide in recent years. China is one of the largest plastic producers in the world. In this review, available information on MPs in China Sea was reviewed, including studies on seawater, sediment, and biota. The status and limits of sampling methods of MPs were summarized, such as sampling tools, sampling volume, and depth of sampling. The analytical methods of MPs were outlined, such as sieving, density separation, purification, filtration, and visual sorting. The characteristics of MPs, such as abundances, sizes, shapes, polymer types, sources, and fates were analyzed. The abundances of MPs in China Sea varied from 0.1 to 27,840.0 items m-3 in seawater, and from 13.0 to 14,712.0 items kg-1 d.w. in sediments. Furthermore, MPs were mainly featured with sizes ranging from 0.001 to 0.5 mm, with colors of transparent and black, and polymer types of polypropylene and polyethylene. To promote research on MPs in China Sea, the sampling and analytical methods were insufficiently standardized and should be improved. As for microplastic (MP) pollution in China Sea, laws and regulations have already been established to manage and control plastic waste. Furthermore, several suggestions to control plastic pollution were as follows: (1) control marine plastic pollution at the source; (2) strengthen technological innovations; (3) urge people to minimize disposable plastic products in their daily lives; (4) strengthen international cooperation in the treatment of marine plastic waste.


Assuntos
Microplásticos , Poluentes Químicos da Água , China , Monitoramento Ambiental , Humanos , Plásticos , Polietileno , Poluentes Químicos da Água/análise
10.
J Hazard Mater ; 421: 126711, 2022 01 05.
Artigo em Inglês | MEDLINE | ID: mdl-34332489

RESUMO

Understanding the interactions between oil and other particles in shoreline can help determine the environmental risk and cleanup strategy after oil spill. Nevertheless, far less has been known regarding the impact of aged MPs on oil behavior in the shoreline environment. In this study, the aging course of polyethylene (PE) in shaking seawater and ultraviolet (UV) radiation conditions was investigated. The seawater aging mainly affected the physical properties of MPs, increasing its surface pores and hydrophilicity. UV aging significantly affected both the physical and chemical properties of MPs, which increased its hydrophilicity and crystallinity, decreased its mean particle size and introduced oxygen-containing functional groups onto MPs. The two-dimensional correlation spectroscopy (2D COS) analysis confirmed the evolution of oxygen-containing functional groups from C-O to CO. The effects of aged MPs on oil behavior in water-sand system were further explored. The oil remaining percentages were non-linearly changed with the increasing aging degree of MPs. The particle size of the aqueous phase after washing was inversely related to the oil remaining percentage. Further FTIR analysis revealed that C-O and C-H functional groups played an important role in the process of oil adsorbed on MPs.


Assuntos
Microplásticos , Poluentes Químicos da Água , Plásticos , Polietileno , Água do Mar , Poluentes Químicos da Água/análise
11.
J Hazard Mater ; 421: 126777, 2022 01 05.
Artigo em Inglês | MEDLINE | ID: mdl-34364209

RESUMO

Microplastics are an emerging environmental issue as a result of their ubiquity, persistence, and intrinsic toxic potential. In addition, their ability to sorb and transport a wide variety of environmental pollutants (i.e. "Trojan Horse" effect) exerts significant adverse impacts upon ecosystems. The toxicological evaluation of the single and combined effects produced by polyethylene microplastics and two polychlorinated biphenyl congeners was performed on the human hepatoma cell line HepG2 by cell viability assessment and an untargeted lipidomic study. The cell lethality evaluation evinced that MPs did not induce relevant cell lethality at any of the concentration range tested, while both PCBs presented a hormetic behavior. The lipidomic analysis suggested that both single PCB exposures induced significant lipidomic changes, especially for glycerophospholipids and glycerolipids. In contrast, for MPs single exposure, the most remarkable change was the substantial enhancement of triglyceride content. Regarding combined exposures, results showed that MPs could induce even more harmful effects than those produced intrinsically as a result of desorbing previously sorbed toxic pollutants. To the best of our knowledge, this is the first study assessing the toxicity of microplastics and their possible "Trojan Horse" effect by applying an untargeted lipidomic methodology.


Assuntos
Carcinoma Hepatocelular , Neoplasias Hepáticas , Bifenilos Policlorados , Ecossistema , Humanos , Lipidômica , Microplásticos , Plásticos/toxicidade , Bifenilos Policlorados/análise , Bifenilos Policlorados/toxicidade , Polietileno/toxicidade
12.
Environ Pollut ; 292(Pt B): 118466, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34767867

RESUMO

Currently, the evidence of the ingestion of microplastics (MPs) by organisms or the accumulation in different environmental compartments has been achieved using several methodological procedures. However, its uses have not been standardized across studies. In this study, we aim to assess and validate a protocol that can be useful for optimizing the identification and quantification procedures of polyethylene microplastics (PE MPs) in biological samples. Initially, considering that numerous studies filter samples previously digested in cellulosic membranes for isolation and analysis of MPs, we evaluated whether washing these membranes with different reagents could contribute to the complete detachment of particles, as well as to their dispersion in the obtained solutions. However, none of the tested reagents (dimethyl sulfoxide, acetone, ethyl alcohol and chloroform), including purified water, was able to completely remove the MPs adhered to the membranes or facilitate their dispersion in the solutions. On the other hand, we observed that the digestion of the membranes by acetonitrile constituted a procedure that prevents the loss of particles due to adherence, in addition to promoting good dispersion of MPs. Subsequently, we evaluated the use of Neubauer chambers for the quantification of MPs, having observed a good recovery rate (>92%) and results with insignificant variation, in PE MPs solutions with different concentrations (0.15; 0.075 and 0.0375 mg/mL). Ultimately, the validation of the proposed procedures took place from the evaluation of the accumulation of PE MPs in Astyanax spp. juveniles, having demonstrated the efficiency and sensitivity of the method proposed for this purpose. Subsequently, our study provides a methodological alternative that can optimize MPs quantifications in biological samples and reduce the generation of biased or unreliable results.


Assuntos
Microplásticos , Poluentes Químicos da Água , Monitoramento Ambiental , Plásticos , Polietileno/análise , Poluentes Químicos da Água/análise
13.
Environ Pollut ; 292(Pt B): 118485, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34774675

RESUMO

Recalcitrant plastics in the environment are gradually fragmented into weathered debris distinguished from their original state by the integrative action of influencing factors, such as UV light, heating and physical abrasion. As new artificial carbon-source substrates in aquatic ecosystems, plastic products can be colonized by biofilms and even utilized by microorganisms. To investigate the influences of weathering of plastics on the colonized biofilms, freshwater samples from the Yangtze River (Nanjing, China) were collected for biofilm incubation. Based on the characterization of plastics and biofilms, the effects of plastic surface properties on biofilm characteristics were revealed by the analysis of partial least squares regression (PLSR). Roughness was the principal influencing factor, while rigidity had the opposite effect to it. 16S rRNA gene high-throughput sequencing results indicated the high relative abundance of Cyanobacteria and rising proportion of harmful components (e.g., Flavobacterium) on photoaged polyethylene plastics. The microbial functional profiles (KEGG) predicted by Tax4Fun showed that the functions (e.g., membrane transport, energy metabolism, etc.) of biofilm on photoaged plastics were dissimilar with those on original ones. These findings suggested that the distinct microbial community and the adverse functional changes in biofilms on photoaged plastics potentially enhanced their environmental risks. On the other hand, 28-day cultured biofilms on original low-density polyethylene (LDPE) films were dominated by Exiguobacterium. The previously ignored potentials of this microorganism in rapidly accommodating to a hydrophobic substrate and its plastic degrading ability were both worthy of attention. Therefore, it is necessary to consider the weathering process of plastics in exploring the "plastisphere", and to give further insights into the double-edged nature of the "plastisphere".


Assuntos
Microbiota , Polietileno , Biofilmes , Plásticos , RNA Ribossômico 16S/genética
14.
Chemosphere ; 286(Pt 3): 131758, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34399255

RESUMO

Wasted polyethylene (PE) products caused pollution has become a global issue. Researchers have identified PE-degrading bacteria which have been considered as a sustainable alleviation to this crisis. However, the degradation mechanism employed by currently isolated bacteria is unclear and their degradation efficiencies are insufficient. More importantly, there is little research into bacteria capable of degrading PE mulching film to solve "white" pollution in agriculture. We determined the PE degradation efficiency of two Pseudomonas, identified by 16S rDNA analysis, and elucidated their potential mechanisms through whole genome sequencing. During an 8-week period, PE mulch lost 5.95 ± 0.03% and 3.62 ± 0.32% of its mass after incubated with P. knackmussii N1-2 and P. aeruginosa RD1-3 strains, respectively. Moreover, considerable pits and wrinkles were observed on PE.The hydrophobicity of PE films also decreased, and new oxygenic functional groups were detected on PE mulch by Fourier Transform Infrared Spectrometry (FTIR). Complete genome sequencing analysis indicated that two Pseudomonas strains encode genes for enzymes and metabolism pathways involved in PE degradation. The results provide a theoretical basis for further research that investigates the mechanism driving the degradation and metabolism of discarded PE in the environment.


Assuntos
Polietileno , Pseudomonas , Agricultura , Bactérias , Biodegradação Ambiental , Pseudomonas/genética
15.
Medicine (Baltimore) ; 100(41): e27454, 2021 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-34731119

RESUMO

RATIONALE: Total hip arthroplasty (THA) with a polyethylene (PE) liner is 1 of the most effective and successful treatment strategies for end-stage hip disorders. Vitamin E-infused highly cross-linked polyethylene is theoretically known to prevent failure due to oxidative degradation in the body, and is resistant to wear; therefore, successful long-term survival of THA is expected. PATIENT CONCERNS: In June 2019, approximately 1.5 years after THA, the patient sat down and stood up without any specific issue; however, an unusual bullet sound occurred around the left hip joint. Since then, his discomfort persisted, and he was admitted to the emergency department. DIAGNOSIS: Plain radiography and metal artifact reduction computed tomography performed in the emergency department revealed eccentric elevation of the prosthetic femoral head and suspected PE liner failure. INTERVENTION: Revision surgery was performed for modular component exchange. To reduce the dislocation risk without performing cup exchange, conversion to dual-mobility articulation was performed. OUTCOMES: During the regular follow-up post-surgery, the patient could perform daily life activities without any discomfort, and dislocation was not observed. At 2 years postoperatively, no significant changes were observed in the radiographic images. LESSONS: This case report presents an unexpected failure of THA due to superior rim fracture and excessive wear at the locking mechanism of the vitamin E-infused highly cross-linked polyethylene liner. This is an interesting case, as early PE liner failure occurred without strong labor intensity or trauma. A modular component exchange was performed with a dual-mobility bearing, and no issues were observed approximately 2 years after the reoperation. Therefore, third-generation highly cross-linked polyethylene liners can also cause early failure without a clear cause, and this case report highlights the necessity of considering several strategies for reoperation. STUDY DESIGN: Case report.


Assuntos
Artroplastia de Quadril/efeitos adversos , Falha de Prótese/efeitos adversos , Prótese de Quadril/efeitos adversos , Humanos , Masculino , Pessoa de Meia-Idade , Polietileno , Desenho de Prótese , Reoperação , Vitamina E
16.
Aquat Toxicol ; 241: 106004, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34739976

RESUMO

Plastic pollution has become a major environmental and societal concern in the last decade. From larger debris to microplastics (MP), this pollution is ubiquitous and particularly affects aquatic ecosystems. MP can be directly or inadvertently ingested by organisms, transferred along the trophic chain, and sometimes translocated into tissues. However, the impacts of such MP exposure on organisms' biological functions are yet to be fully understood. Here, we used a multi-diagnostic approach at multiple levels of biological organization (from atoms to organisms) to determine how MP affect the biology of a marine fish, the gilthead seabream, Sparus aurata. We exposed juvenile seabreams for 35 days to spherical 10-20 µm polyethylene primary MP through food (Artemia salina pre-exposed to MP) at a concentration of 5 ± 1 µg of MP per gram of fish per day. MP-exposed fish experienced higher mortality, increased abundance of several brain and liver primary metabolites, hepatic and intestinal histological defects, higher assimilation of an essential element (Zn), and lower assimilation of a non-essential element (Ag). In contrast, growth and muscle C/N isotopic profiles were similar between control and MP-exposed fish, while variable patterns were observed for the intestinal microbiome. This comprehensive analysis of biological responses to MP exposure reveals how MP ingestion can cause negligible to profound effects in a fish species and contributes towards a better understanding of the causal mechanisms of its toxicity.


Assuntos
Dourada , Poluentes Químicos da Água , Animais , Ecossistema , Monitoramento Ambiental , Microplásticos , Plásticos/toxicidade , Polietileno/toxicidade , Poluentes Químicos da Água/toxicidade
17.
Bone Joint J ; 103-B(11): 1695-1701, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34719265

RESUMO

AIMS: Wear of the polyethylene (PE) tibial insert of total knee arthroplasty (TKA) increases the risk of revision surgery with a significant cost burden on the healthcare system. This study quantifies wear performance of tibial inserts in a large and diverse series of retrieved TKAs to evaluate the effect of factors related to the patient, knee design, and bearing material on tibial insert wear performance. METHODS: An institutional review board-approved retrieval archive was surveyed for modular PE tibial inserts over a range of in vivo duration (mean 58 months (0 to 290)). Five knee designs, totalling 1,585 devices, were studied. Insert wear was estimated from measured thickness change using a previously published method. Linear regression statistical analyses were used to test association of 12 patient and implant design variables with calculated wear rate. RESULTS: Five patient-specific variables and seven implant-specific variables were evaluated for significant association with lower insert wear rate. Six were significant when controlling for other factors: greater patient age, female sex, shorter duration in vivo, polished tray, highly cross-linked PE (HXLPE), and constrained knee design. CONCLUSION: This study confirmed that knee wear rate increased with duration in vivo. Older patients and females had significantly lower wear rates. Polished modular tibial tray surfaces, HXLPE, and constrained TKA designs were device design factors associated with significantly reduced wear rate. Cite this article: Bone Joint J 2021;103-B(11):1695-1701.


Assuntos
Artroplastia do Joelho , Prótese do Joelho , Polietileno , Desenho de Prótese , Falha de Prótese , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos
18.
Int J Nanomedicine ; 16: 7479-7494, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34785895

RESUMO

Purpose: Wear debris particle-induced periprosthetic osteolysis is a severe complication of total joint replacement that results in aseptic loosening and subsequent arthroplasty failure. No effective therapeutic agents or drugs have been approved to prevent or treat osteolysis; thus, revision surgery is often needed. Extracellular vesicles (EVs) are vital nanosized regulators of intercellular communication that can be directly applied to promote tissue repair and regeneration. In this study, we assessed the therapeutic potential of EVs from human urine-derived stem cells (USCs) (USC-EVs) in preventing ultrahigh-molecular-weight polyethylene (UHMWPE) particle-induced osteolysis. Methods: USCs were characterized by measuring induced multipotent differentiation and flow cytometry. USC-EVs were isolated and characterized using transmission electron microscopy (TEM), dynamic light scattering (DLS) and Western blotting. RAW264.7 cells and bone marrow mesenchymal stem cells (BMSCs) were cultured with USC-EVs to verify osteoclast differentiation and osteoblast formation, respectively, in vitro. The effects of USC-EVs were investigated on a UHMWPE particle-induced murine calvarial osteolysis model by assessing bone mass, the inflammatory reaction, and osteoblast and osteoclast formation. Results: USCs differentiated into osteogenic, adipogenic and chondrogenic cells in vitro and were positive for CD44, CD73, CD29 and CD90 but negative for CD34 and CD45. USC-EVs exhibited a cup-like morphology with a double-layered membrane structure and were positive for CD63 and TSG101 and negative for calnexin. In vitro, USC-EVs promoted the osteogenic differentiation of BMSCs and reduced proinflammatory factor production and osteoclastic activity in RAW264.7 cells. In vivo, local injection of USC-EVs around the central sites of the calvaria decreased inflammatory cytokine generation and osteolysis compared with the control groups and significantly increased bone formation. Conclusion: Based on our findings, USC-EVs prevent UHMWPE particle-induced osteolysis by decreasing inflammation, suppressing bone resorption and promoting bone formation.


Assuntos
Vesículas Extracelulares , Osteólise , Animais , Humanos , Camundongos , Osteoclastos , Osteogênese , Osteólise/induzido quimicamente , Polietileno , Células-Tronco
19.
Life Sci Space Res (Amst) ; 31: 71-79, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34689952

RESUMO

Energetic ion beam experiments with major space radiation elements, 1H, 4He, 16O, 28Si and 56Fe, have been conducted to investigate the radiation shielding properties of composite materials. These materials are expected to be used for parts and fixtures of space vehicles due to both their mechanical strength and their space radiation shielding capabilities. Low Z materials containing hydrogen are effective for shielding protons and heavy ions due to their high stopping power and large fragmentation cross section per unit mass. The stopping power of the composite materials used in this work is intermediate between that of aluminum and polyethylene, which are typical structural and shielding materials used in space. The total charge-changing cross sections per unit mass, σUM, of the composite materials are 1.3-1.8 times larger than that of aluminum. By replacing conventional aluminum used for spacecraft with commercially available composite (carbon fiber / polyether ether ketone), it is expected that the shielding effect is increased by ∼17%. The utilization of composite materials will help mitigate the space radiation hazard on future deep space missions.


Assuntos
Radiação Cósmica , Íons Pesados , Proteção Radiológica , Voo Espacial , Polietileno , Doses de Radiação , Astronave
20.
Artigo em Inglês | MEDLINE | ID: mdl-34682374

RESUMO

Accumulation of micro-plastics (MPs) in the environment has resulted in various ecological and health concerns. Nowadays, however, studies are mainly focused on toxicity of MPs on aquatic organisms, but only a few studies assess the toxic effects of micro-plastics on terrestrial plants, especially edible agricultural crops. The present study was aimed to investigate the adverse effects of polyethylene (PE) microplastics on the germination of two common food crops of China, i.e., soybean (Glycine max) and mung bean (Vigna radiata). Both the crops were treated with polyethylene microplastics (PE-MPs) of two sizes (6.5 µm and 13 µm) with six different concentrations (0, 10, 50, 100, 200, and 500 mg/L). Parameters studied were (i) seed vigor (e.g., germination energy, germination index, vigor index, mean germination speed, germination rate); (ii) morphology (e.g., root length, shoot length) and (iii) dry weight. It was found that the phyto-toxicity of PE-MPs to soybean (Glycine max) was greater than that of mung bean (Vigna radiata). On the 3rd day, the dry weight of soybean was inhibited at different concentrations as compared to the control and the inhibition showed decline with the increase in the concentration of PE-MPs. After the 7th day, the root length of soybean was inhibited by PE-MPs of 13 µm size, and the inhibition degree was positively correlated with the concentration, whereas the root length of mung bean was increased, and the promotion degree was positively correlated with the concentration. Present study indicated the necessity to explore the hazardous effects of different sizes of PE-MPs on the growth and germination process of agricultural crops. Additionally, our results can provide theoretical basis and data support for further investigation on the toxicity of PE-MPs to soybean and mung bean.


Assuntos
Vigna , Produtos Agrícolas , Germinação , Microplásticos , Plásticos , Polietileno/toxicidade , Soja
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