A novel puzzle ring replacement technique of a lumen-apposing metal stent with a double-pigtail plastic stent to prevent walled-off necrosis recurrence (with video).

Replacing a lumen-apposing metal stent (LAMS) with a double-pigtail plastic stent (DPS) after treatment for walled-off necrosis contributes to the prevention of recurrence. However, the success rate is not very high. To overcome this issue, we devised a novel stent-replacement technique. In the final treatment procedure, a 7-F DPS was placed in the lumen of the LAMS. Subsequently, the walled-off necrosis shrank, and granulation formed over the pigtail portion, which fixed the DPS. The LAMS alone was removed with grasping forceps, leaving the DPS in the lumen of the LAMS (i.e., a puzzle-ring technique; direct or rotary removal technique). Between August 2021 and August 2023, 18 patients were evaluated for recurrence prevention using this novel technique (median duration of LAMS placement, 37 days). In 17 patients (94.4%), the LAMS was successfully replaced with a 7-F DPS (direct technique 14, rotary technique 3; median removal procedure time, 3 min). No recurrence was observed during the median observation period of 385 days. Before using this technique (April 2012 to August 2022), the technical success rate of replacement of LAMS with 7-F DPS was significantly lower (61.8% [42/68, p = 0.02]). Recurrence of pancreatic fluid collection occurred in 15.3% (4/26) of the patients who could not undergo replacement with a 7-F DPS. The novel puzzle ring technique, which improves the success rate of LAMS for DPS replacement, may be useful in reducing recurrence after walled-off necrosis treatment.

Combining slow-release fertilizer and plastic film mulching reduced the carbon footprint and enhanced maize yield on the Loess Plateau.

Agricultural practices significantly contribute to greenhouse gas (GHG) emissions, necessitating cleaner production technologies to reduce environmental pressure and achieve sustainable maize production. Plastic film mulching is commonly used in the Loess Plateau region. Incorporating slow-release fertilizers as a replacement for urea within this practice can reduce nitrogen losses and enhance crop productivity. Combining these techniques represents a novel agricultural approach in semi-arid areas. However, the impact of this integration on soil carbon storage (SOCS), carbon footprint (CF), and economic benefits has received limited research attention. Therefore, we conducted an eight-year study (2015-2022) in the semi-arid northwestern region to quantify the effects of four treatments [urea supplied without plastic film mulching (CK-U), slow-release fertilizer supplied without plastic film mulching (CK-S), urea supplied with plastic film mulching (PM-U), and slow-release fertilizer supplied with plastic film mulching (PM-S)] on soil fertility, economic and environmental benefits. The results revealed that nitrogen fertilizer was the primary contributor to total GHG emissions (≥71.97%). Compared to other treatments, PM-S increased average grain yield by 12.01%-37.89%, water use efficiency by 9.19%-23.33%, nitrogen accumulation by 27.07%-66.19%, and net return by 6.21%-29.57%. Furthermore, PM-S decreased CF by 12.87%-44.31% and CF per net return by 14.25%-41.16%. After eight years, PM-S increased SOCS (0-40 cm) by 2.46%, while PM-U decreased it by 7.09%. These findings highlight the positive effects of PM-S on surface soil fertility, economic gains, and environmental benefits in spring maize production on the Loess Plateau, underscoring its potential for widespread adoption and application.

Rapid detection of colored and colorless macro- and micro-plastics in complex environment via near-infrared spectroscopy and machine learning.

To better understand the migration behavior of plastic fragments in the environment, development of rapid non-destructive methods for in-situ identification and characterization of plastic fragments is necessary. However, most of the studies had focused only on colored plastic fragments, ignoring colorless plastic fragments and the effects of different environmental media (backgrounds), thus underestimating their abundance. To address this issue, the present study used near-infrared spectroscopy to compare the identification of colored and colorless plastic fragments based on partial least squares-discriminant analysis (PLS-DA), extreme gradient boost, support vector machine and random forest classifier. The effects of polymer color, type, thickness, and background on the plastic fragments classification were evaluated. PLS-DA presented the best and most stable outcome, with higher robustness and lower misclassification rate. All models frequently misinterpreted colorless plastic fragments and its background when the fragment thickness was less than 0.1mm. A two-stage modeling method, which first distinguishes the plastic types and then identifies colorless plastic fragments that had been misclassified as background, was proposed. The method presented an accuracy higher than 99% in different backgrounds. In summary, this study developed a novel method for rapid and synchronous identification of colored and colorless plastic fragments under complex environmental backgrounds.

Highly degradable bio-based plastic with water-assisted shaping process and exceptional mechanical properties.

The fabrication of biodegradable and recyclable bio-based plastic by complexing carboxymethyl cellulose (CMC) and cationic polymeric ionic liquid (PILCl) assisted with KNO3 is offered to utilize plastics sustainably and mitigate serious threats to the environment. The CMC/PIL plastic film, formed via electrostatic interactions, exhibits exceptional mechanical properties that surpass those of most conventional plastics. It demonstrates a tensile strength of approximately 200 MPa and a Young's modulus of around 5.5GPa. Even after recycling and regeneration, they essentially retain the original mechanical characteristics with a tensile strength of about 190 MPa. These CMC/PIL plastic films can be processed into three-dimensional (3D) shapes assisted with water and their fundamental qualities maintain after numerous shaping. Besides, they possess excellent biodegradability and can finish biodegrading in a few hours with cellulase and within a few days when exposed to soil. This innovation provides a fresh and practical way to produce degradable plastics.

Environmental and economic assessment of mixed plastic waste pelletization in the Gulf Cooperation Council region.

Pelletizing mixed plastic wastes (MPW) has gained interest as an upcycling technology and an alternative to conventional recycling. To investigate its potential, we conducted a cost analysis and life-cycle assessment (LCA) for a conceptual pelletization facility designed to produce 1 kg of pellets per batch of MPW (comprising polyethylene-PE and polypropylene-PP). This work has the following merits: (i) evaluating environmental impact (EI), cost analysis, and mechanical strength based on actual experimental data and its comparison with local and international manufacturers; (ii) enabling the evaluation of LCA impacts of MPW pellets; and (iii) emphasizing the significance of waste management in reducing EIs. The following ten EIs were assessed: climate change (CC), net energy, particulate matter formation, natural land transformation, metal depletion, marine ecotoxicity, ionising radiation, freshwater ecotoxicity, freshwater eutrophication, and terrestrial ecotoxicity. The CC of the as-synthesized pellets is 1.26 kg CO2 eq., significantly lower than the data obtained from the Gulf Petrochemicals and Chemicals Association (GPCA) and an actual plant in Gulf Cooperation Council (GCC) countries. Additionally, the net energy required for the production of 1 kg of pellets is 54.1 MJ, while the cost is around 0.55 USD. The tensile strength of MPW pellets (24.63 MPa) falls between that of PE virgin pellets (21.12 MPa) and PP virgin pellets (28.12 MPa). This suggests that the MPW pellets exhibit competitive strength characteristics, warranting its consideration for applications where moderate strength is required. Overall, the competitive cost, coupled with the reduced EIs, demonstrates the potential of pelletization as a sustainable and economically viable waste management solution.

Multigenerational effects of combined exposure of triphenyltin and micro/nanoplastics on marine medaka (Oryzias melastigma): From molecular levels to behavioral response.

In natural environments, micro/nanoplastics (MNP) inevitably coexist with various pollutants, making it essential to examine their combined toxicity and intergenerational effects on marine organisms. This study investigated the combined toxicity and intergenerational effects of exposure to triphenyltin (T), microplastics (M), nanoplastics (N), a combination of microplastics and triphenyltin (MT), and a combination of nanoplastics and triphenyltin (NT) on marine medaka. The results showed that all treatments had adverse and intergenerational effects on marine medaka. Regarding oxidative stress and energy metabolism, smaller sized plastic particles caused more significant damage to the organisms. However, MT inflicted greater gonadal system damage than NT, leading to imbalanced sex hormone levels. Additionally, T induced hyperactivity in fish, whereas MNP tended to induce behavioral depression. Notably, large plastic particles in the F0 generation had a more pronounced impact on depressive behaviors compared to smaller particles. These findings suggest that both individual and combined exposures to TPT and MNP can detrimentally affect marine medaka from the molecular to behavioral levels, posing risks to population sustainability. This study provided a robust theoretical foundation and deeper insights into the ecotoxicological impacts and risk assessments of coexisting pollutants.

Phthalate ester and cholesterol profiles of blubber samples of the free-ranging Amazon River dolphin (Cetacea: Iniidae: Inia geoffrensis) in the Brazilian Amazon.

This study assessed the exposure of free-ranging Amazon River dolphins (Inia geoffrensis) to phthalate esters (PAE) in a remote area of the Brazilian Amazon. Blubber samples were analyzed for four PAEs - dimethyl phthalate, diethyl phthalate, dibutyl phthalate, and di(2-ethylhexyl) phthalate - and cholesterol contents to evaluate potential metabolic disturbances. All dolphins were contaminated with at least two PAEs, with DEHP (242.16 ng/µL) and DBP (191.62 ng/µL) being the most frequent, detected in 93 % and 79 % of the sample, respectively. Significant positive correlations were found between DBP and DEP (r = 0.857), DEHP and DEP (r = 0.794), and DBP and body length (r = 0.642), suggesting bioaccumulation. Despite the cholesterol data not showing a correlation with the other findings, these results highlight PAE pollution in a supposedly pristine environment and their potential impact on the health and conservation of Amazon River dolphins' health and Amazonian ecosystem.

Microplastic characteristics in rain/snow sampled from two northern Chinese cities.

Atmospheric precipitation is recognized as a significant source of environmental microplastics, especially in inland waters and remote areas. However, due to the limited availability of existing data, further information on microplastics in precipitation is essential. Therefore, this study aims to elucidate the contamination of microplastics in both snowfall and rainfall while identifying potential factors that may influence their presence during atmospheric deposition. Samples of snowfall and rainfall were collected from two representative cities in Northern China across winter and summer seasons. Subsequently, microplastics were identified and quantified automatically using laser-assisted direct infrared imaging techniques. The findings indicate that microplastic concentrations are higher in snowfall (City A: 182.30 ±â€¯190.25 items/L; City B: 301.74 ±â€¯325.81 items/L) compared to rainfall (City A: 58.90 ±â€¯51.00 items/L; City B: 39.20 ±â€¯30.31 items/L), revealing significant variations in the polymer composition of microplastics. Moreover, a greater diversity of polymers was identified in snowfall relative to rainfall, despite some commonalities among polymers; fragments measuring between 20 µm to 100 µm comprised the majority of detected microplastic particles across both types of precipitation. Crucially, the frequency of precipitation events (rainfall versus snowfall) appears to affect the concentration of atmospheric microplastics, resulting in notably higher levels within snowfalls. These findings offer valuable insights into wet deposition processes by underscoring the atmospheric origins contributing to environmental microplastic pollution.

Comparison of Sexual Function, Satisfaction, and Assertiveness in Genital Cosmetic Surgery Groups: A Randomized-Sampling Cross-Sectional Study.

BACKGROUND: Sexual dissatisfaction is one of the main motivations for seeking female genital cosmetic surgery (FGCS), though the outcomes of such surgeries are controversial. OBJECTIVES: Evaluation of the sexual function, satisfaction, and assertiveness in FGCS groups. METHODS: From five clinical centers in Tehran, Iran, 200 women in the study group (women seeking or had undergone labiaplasty (LP), women seeking or had undergone multi-procedure (MP) of FGCS simultaneously) and the control group were randomly selected. Participants completed the Female Sexual Function Index (FSFI), the Global Measure of Sexual Satisfaction (GMSEX), and the Hurlbert Index of Sexual Assertiveness (HISA). The groups were compared using the Chi-square, one-way ANOVA with post hoc analysis. RESULTS: In women seeking LP, the mean FSFI, GMSEX, and HISA score was lower than that of women who had undergone LP (FSFI: 18.41 vs 21.36, p =0.04, GMSEX: 20.36 vs 28.03 p <0.001, HISA: 49.7 vs 62.5 p <0.001). Our finding showed as well that women seeking MP also had lower mean FSFI, GMSEX, and HISA score compared to women had undergone MP (FSFI: 23.02 vs 18.02, p <0.001, GMSEX: 19.63 vs 28.94 p <0.001, HISA: 45.72 vs 60.62 p <0.001). CONCLUSION: Women who had completed FGCS experienced better sexual function, satisfaction, and assertiveness compared with women seeking surgery. LEVEL OF EVIDENCE III: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Recyclable Robust Plastic Scintillation Resin Achieving the Exceptional Separation and Detection of Technetium-99.

Rapid detection and absorption of 99TcO4 ⁻ contamination in the environment are critical due to its high radioactivity, long half-life, and significant environmental mobility. Resins have been demonstrated effective bifunctional properties for both the detection and separation of 99TcO4 ⁻. However, the poor stability of these compounds limits their practical application. Here, a chemical grafting strategy is presented to synthesize ultra-stable plastic scintillation resin, in which 4-vinylpyridine and divinylbenzene are cross-linked as matrix polymer to withstand extreme conditions and a fluorophore "shield" to convert beta radiation into detectable signals. As expected, the as-obtained resin exhibits a high adsorption capacity of 549.2 mg g⁻¹ for 99TcO4 ⁻ with a rapid kinetic response of just 10 min as well as superior selectivity at 1000 times excess of interfering ions and full reusability. Moreover, it showed remarkable stability under 800 kGy, 3.0 mol L-1 HNO3 or 2.5 L solution continuous leaching, consistently maintaining high separation and detection efficiency after recycling 10 times. This strategy paves a new way to develop stable resin for the rapid capture and accurate measurement of 99TcO4 ⁻, which owns great potential for practical application.

Exploring biodegradable alternatives: microorganism-mediated plastic degradation and environmental policies for sustainable plastic management.

Plastics offer versatility, durability and low production costs, but they also pose environmental and health risks due to improper disposal, accumulation in water bodies, low recycling rates and temporal action that causes physicochemical changes in plastics and the release of toxic products to animal health and nature. Some microorganisms may play crucial roles in improving plastic waste management in the future. Cunningamella echinulata has been identified as a promising candidate that remains viable for long periods and produces a cutinase that is capable of degrading plastic. Other recent approaches involving the use of microorganisms are discussed in this review. However, there does not seem to be a single science that is efficient or most appropriate for solving the problem of plastic pollution on the planet at present. Regulations, especially the implementation of different laws that address the entire plastic cycle in different countries, such as Brazil, the USA, China and the European Union, play important roles in the management of this waste and can contribute to reducing this problem. In the context of the transversality of the information compiled here, the current limitations are discussed, and an effective plan is proposed to reduce plastic pollution. Although it is challenging, it involves implementing legislation, promoting sustainable alternatives, improving collection and recycling systems, encouraging reuse, supporting research and technological innovation, promoting corporate responsibility, collaborating globally, raising public awareness, optimizing waste management and, above all, continuously monitoring the progress of actions based on measurable metrics.

Disintegration of certified compostable plastic bags in outdoor household composting conditions.

Picking up dog faeces with single use plastic bags and disposing in landfill is a common practice which ultimately harms the environment. Compostable plastic dog waste bags may help to divert these wastes from landfill and recover dog faeces as a compost feedstock, though little is known about how certified home compostable plastics behave in real world home compost systems. This study investigated the disintegration of commercially available certified home compostable plastic bags in outdoor home composts containing dog faeces. Two pilot trials (25 L) and one household trial (160 L) were conducted over 7, 15, and 9.5 months, respectively. Thermophilic temperatures were reached in all trials while moisture and pH were within optimal ranges for well managed compost systems. Bags showed statistically significant differences in disintegration. Based on final mass, none of the tested bags met the Australian Standard AS5810 minimum disintegration requirements of 90 % mass loss of plastic fragments >2 mm, with average mass change of certified home compostable bags ranging from +1.51 to -81.28 %. All certified industrial compostable bags showed an average mass increase of 10.90-35.04 % during composting. However, time series images of plastic fragmentation indicated some bags fully disintegrated and revealed residual biofilm that may have affected mass change data. Microplastic fragments < 2mm and macroplastic fragments >5 mm were recovered in all composts. Due to the potential risks of using home compost contaminated with microplastics in household gardens, dog owners should avoid including compostable plastic bags in their home composts.

What influences the on-site recycling behaviour of C&D plastic waste in Australia? An action determination model approach.

While the recycling of construction waste has received widespread attention, plastic waste generated at construction sites has been overlooked. At the same time, existing studies on pro-environmental behaviour have only considered practical knowledge of implementing recycling, while ignoring the possible impact of circular economy knowledge on recycling behaviour. This study investigates on-site personnel's behaviour regarding C&D plastic waste recycling through the lens of the comprehensive action determination model (CADM), which uniquely incorporates behaviour as a key variable and extends with moderating effect of knowledge of the circular economy. Utilizing Partial Least Squares Structural Equation Modelling (PLS-SEM), results indicate that perceived behavioural control is the most substantial factor influencing recycling behaviour of plastic waste on construction sites rather than intention. This is in stark contrast to existing pro-environmental behaviours research and reflects the importance of providing resources and encouragement to increase personnel's confidence in performing recycling behaviours on site, contributing more to actual behaviours than intention. Key areas for improvement were identified, including management encouragement, resource allocation (site area, timeline, budget), and recycling training. Contrary to expectations, awareness of the circular economy did not statistically significantly moderate the predictors of recycling behaviour and intentions, perhaps because participants had limited knowledge of plastic consumption and recycling rates in the construction industry. As construction personnel become more familiar with the circular economy, future research should re-evaluate these moderating effects and consider conducting categorical moderation analyses with larger sample sizes, incorporating variables such as work experience, project type, and project phase.

Enzymatic oxidation of polyethylene by Galleria mellonella intestinal cytochrome P450s.

Polyethylene is widely used but highly resistant to biodegradation, owing to its composition of only a hydrocarbon backbone. For biodegradation to occur, oxidation within the polymer needs to be initiated. Galleria mellonella was the first insect discovered to autonomously oxidize polyethylene without the aid of gut microbes. However, the specific enzyme remains unidentified. Here, we identified for the first time two polyethylene oxidation enzyme candidates of cytochrome P450 (CYP) 6B2-GP04 and CYP6B2-13G08 from the G. mellonella midgut. Both candidate clones oxidized polyethylene efficiently, generating short-chain aliphatic compounds, with CYP6B2-GP04 exhibiting higher activity than CYP6B2-13G08 in yeast and insect cells. In silico structural modeling approaches revealed that the CYP6B2-GP04 Phe118 was essential for interacting with hydrocarbons, which was further validated by mutating phenylalanine to glycine. Furthermore, directed enzyme evolution led to the identification of an enzyme variant with significantly increased oxidation efficiency. Our findings offer promising enzyme-based solutions for polyethylene biodegradation, potentially mitigating polyethylene-driven plastic pollution.

High frequency of plastic ingestion in procellariiform seabirds (albatrosses, petrels and shearwaters) in the Southwest Atlantic Ocean.

Ocean pollution by plastics is a growing concern for marine wildlife conservation, and seabirds are particularly prone to ingest plastics. We report baseline information on plastic ingestion in 17 procellariiform species along the coast of Brazil and Argentina. Through a collaborative regional effort we found plastic items in 30.2 % of seabird carcasses examined (n = 192), comprised predominantly by mesoplastics (5-25 mm), user plastics, polypropylene, polystyrene and polyethylene. Considering the most representative source-site cohorts, the frequency of occurrence of plastic items varied significantly between sampling site and source of carcasses. Ingestion was highest in petrels and shearwaters. Immature birds ingested the largest number (and total mass) of plastic items followed by chicks and adults. Long-term programs applying standardized sampling protocols are needed to detect spatiotemporal patterns of plastic ingestion across species, and assess the potential effectiveness of remediation actions. Further studies are necessary to assess currently unrecognized health effects of plastic ingestion.

Migration patterns of phthalic acid esters from mulch plastic film in the soil-plant-atmosphere continuum system.

Plastic film mulching is an important agricultural practice, but its release of phthalic acid esters (PAEs) poses threats to soil and human health. However, the migration patterns of PAEs during the lifecycle of mulch plastic film (MPF) remain unclear. This study aims to explore the temporal patterns of release of PAEs during the MPF's lifecycle and evaluate the migration patterns of PAEs from MPF in the soil-plant-atmosphere continuum (SPAC) system through pot experiments and model simulations. The results reveal that during the mulching period, 44.90-56.71 % of the PAEs released went into the atmosphere and 14.97-18.90 % into the soil, while during the residual film period, 24.39-40.13 % were slowly released into the soil. Elevated soil water content increased maize transpiration rates, leading to higher concentrations of PAEs in roots, stems, and fruits, but lower concentrations in leaves. In 2020, the estimated total release of PAEs from MPF in northwest China amounted to 35.42 tons. Notably, PAEs predominantly accumulated in the soil, with minimal accumulation in plant tissues. Moreover, PAEs were primarily removed through degradation. Our results elucidate the migration patterns of PAEs from MPF in the SPAC system, facilitating the evaluation of PAE pathways into the human food chain.

A systematic review on sustainable utilization of plastic waste in asphalt: assessing environmental and health impact, performance, and economic viability.

Increasing amount of plastic waste (PW) poses a global challenge that necessitates multifaceted strategies. Repurposing PW in asphalt pavement is a sustainable strategy with extensive benefits, but there are several challenges that need to be overcome. This systematic review aims to examine three significant aspects associated with plastic-modified asphalt: environmental and health considerations, performance and technical properties, and cost.-effectiveness and economic feasibility. The environmental and health impacts of using PW in asphalt were particularly focused on the release of carcinogenic compounds and harmful fumes like polyaromatic hydrocarbons (PAHs) and volatile organic compounds (VOCs), microplastic pollution, and climate impact. Environmental challenges and potential health risks associated with the use of PW in asphalt production were analyzed and indicated. Afterwards, the effects of different plastic types on the fatigue and rutting resistance of asphalt pavement are investigated. While many types of PWs show potential for enhancing rutting and fatigue performance, conflicting results have been observed for certain plastics. Some PW types, such as polyvinyl chloride (PVC), polypropylene (PP), polystyrene (PS), low-density polyethylene (LDPE), and high-density polyethylene (HDPE), have been shown to yield inconsistent results. Lastly, factors that are recognized to have an impact on the cost-effectiveness of plastic-modified asphalt include the collection and processing costs, asphalt materials price and availability, incorporation method, and possible changes in the asphalt's lifespan. The findings of this review help researchers to identify current gaps and aid stakeholders in making informed decisions towards more environmentally friendly, high-performance, and economically viable approaches to asphalt production.

Country-wide assessment of plastic removal rates on riverbanks and water surfaces.

Plastic pollution in river basins poses a significant environmental challenge, particularly in Japan, located in the northwestern North Pacific, often referred to as a hotspot for plastics. This study quantified the annual recovery of anthropogenic plastic litter from riverbanks and water surfaces, utilizing a nationwide cleanup dataset provided by the Japanese Ministry of Land, Infrastructure, Transport and Tourism. The dataset includes the amount of litter recovered through volunteer and administrative cleanup campaigns from 2016 to 2020 in 109 Japanese river basins. Total plastic recovery ranged from 763 to 1177 tons/year, averaging 938 tons/year. Basin-specific recovery was associated with extreme weather events, such as typhoon approaches and heavy rain, which caused significant flood damage in local regions. The estimated annual plastic recovery was an order of magnitude smaller than the previously estimated annual emission of land-based plastic.

Comparison of different fragmentation techniques for the production of true-to-life microplastics.

Microplastics are small plastic particles found widely in the environment, posing significant challenges as diverse environmental contaminants. Their pervasive presence and potential impacts on ecosystems and human health underscore the importance of research in this field. However, working with microplastics in the laboratory and field can be challenging due to the difficulty in creating particles that are similar to those found in the environment. The advancement of research in this area is, therefore, dependent on the availability of reference materials or representative test materials that can simulate real-world conditions. One of the biggest challenges in creating more relevant test microplastics is investigating processes that can mimic as close as possible the environmental counterpart. To tackle this challenge, we have explored three distinct cryogenic grinding techniques for generating microplastics on a laboratory scale (ultracentrifugal mill, immersion blender, mixer mill). The resulting products were examined, and the advantages and limitations of the technologies were analyzed to gain deeper insights into the correlation between the various techniques utilized and the distinctive characteristics of the "true-to-life" microplastics produced. This allows us to tailor the production of test materials to the specific research questions they are intended to address. Furthermore, by understanding the characteristics of true-to-life microplastics, we can gain insights into their behavior under various environmental conditions. This knowledge can help in developing better methods for detecting and monitoring microplastics in the environment, as well as developing more effective mitigation strategies to reduce their impact.

Exploring the effect of greenhouse covering cultivation on the changes of sensory quality and flavor substances of green tea.

To protect tea plant (Camellia sinensis (L.) O. Kuntze) from freezing injury, plastic greenhouse covering is widely used in northern tea areas of China. Currently, there was few researches about the effect of greenhouse covering on tea quality. Our results showed greenhouse covering increased tea yield, changed leaf phenotype and decreased green tea quality. Further analysis revealed greenhouse increased the content of soluble sugars and decreased the content of EGCG and 14 amino acids. Besides, there were 223 differential volatile components were identified in green tea produced by fresh leaves with plastic greenhouse covering (GT) and green tea produced by fresh leaves without plastic greenhouse covering (TT). 81 key aroma components were contributors to the bean-like aroma of TT. 98 key aroma components contributed to the clean aroma of GT. Based on these results, the flavor wheels were constructed, providing a visual presentation of flavor between TT and GT.