polyethylene

聚乙烯
  • 文章类型: Journal Article
    The present Bayesian network meta-analysis compared different types of polyethylene liners in total hip arthroplasty (THA) in terms of wear penetration (mm/year) and rate of revision. The type of liners compared were the crosslinked ultra-high molecular weight polyethylene (CPE/UHMWPE), Vitamin E infused highly cross-linked polyethylene (HXLPE-VEPE), modified cross-linked polyethylene (MXLPE), highly cross-linked polyethylene (HXLPE), Cross-linked polyethylene (XLPE). This study was conducted according to the PRISMA extension statement for reporting systematic reviews incorporating network meta-analyses of healthcare interventions. In June 2024, PubMed, Scopus, Embase, Google Scholar, and Cochrane databases were accessed. A time constraint was set from January 2000. All investigations which compared two or more types of polyethylene liners for THA were accessed. Only studies that clearly stated the nature of the liner were included. Data from 60 studies (37,352 THAs) were collected. 56% of patients were women. The mean age of patients was 60.0 ± 6.6 years, the mean BMI was 27.5 ± 2.0 kg/m2. The mean length of follow-up was 81.6 ± 44.4 months. Comparability was found at baseline between groups. XLPE and HXLPE liners in THA are associated with the lowest wear penetration (mm/year) and the lowest revision rate at approximately 7 years of follow-up.
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  • 文章类型: Journal Article
    目的:描述我们使用新型高密度聚乙烯基球形整合多孔轨道植入物(Oculfit)超过6年的经验。
    方法:这是一项观察性回顾性病例系列研究,分析了2015年2月至2021年9月之间需要Oculfit植入物的所有病例。有关人群的临床信息包括,植入物的特点,并记录了随访期间的结局和并发症.根据解剖和功能参数定义植入物的成功。
    结果:本研究分析了90例眼科患者。摘除或去内脏的主要原因是眼部代偿失调(36.7%)和肿瘤(27.8%的葡萄膜黑色素瘤和7.8%的视网膜母细胞瘤)。在63例(70.0%)中确定了解剖成功,功能成功79例(87.8%),完全成功(解剖功能)61例(67.7%)。与功能成功相关的因素是年龄和主要眼眶植入物的暴露。11例(12.2%)出现并发症,4例(4.4%)完全解决,无后遗症。5例(5.6%)需要轨道外植体。
    结论:根据我们的经验,Oculfit可以被认为是当前可用的眼眶植入物选择中的有用替代品,并且具有良好的疗效/安全性。
    OBJECTIVE: To describe our experience over 6 years using a new high-density polyethylene-based spherical integrated porous orbital implants (Oculfit).
    METHODS: This is an observational retrospective case series study analyzing all cases requiring Oculfit implants between February 2015 and September 2021. Clinical information regarding the population included, the characteristics of the implant, and the outcomes and complications during the follow-up were noted. The success of the implant was defined according to anatomical and functional parameters.
    RESULTS: The study analyzed 90 cases of anophthalmic patients. The main causes for enucleation or evisceration were ocular decompensations (36.7%) and neoplasms (27.8% uveal melanoma and 7.8% retinoblastoma). Anatomical success was identified in 63 (70.0%) cases, functional success in 79 (87.8%) and complete success (anatomical + functional) in 61 (67.7%) cases. Factors associated with the functional success were age and exposure of the primary orbital implant. Complications appeared in 11 (12.2%) cases, which were completely resolved without sequelae in 4 (4.4%). Orbital explant was required in 5 (5.6%) cases.
    CONCLUSIONS: In our experience, Oculfit can be considered a useful alternative among the currently available options for orbital implants and has a good efficacy/safety profile.
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  • 文章类型: Journal Article
    随着工业和现代制造业的发展,不可降解的低密度聚乙烯(LDPE)得到了广泛的应用,对自然生态系统和公众健康构成日益严重的环境危害。在这项研究中,我们从垃圾填埋场中分离出一系列降解LDPE的真菌,并通过成对组合高效降解真菌进行了LDPE降解实验。结果表明,由链格孢菌组成的混合微生物。CPEF-1和Trametessp.PE2F-4(H-3基团)对热处理的LDPE(T-LDPE)具有较大的降解效果。用组合菌株H-3接种30天后,T-LDPE膜的重量损失率比未处理的LDPE(U-LDPE)膜高大约154%,失重率达到0.66±0.06%。环境扫描电子显微镜(ESEM)和傅里叶变换红外光谱(FTIR)进一步研究了T-LDPE的生物降解影响,包括在真菌降解过程中LDPE薄膜的表面变化和解聚。我们的发现表明,联合真菌处理比单一菌株处理更有效地降解T-LDPE。预计适当改变微生物群落的组成可以帮助减轻塑料对环境的有害影响。
    With the development of industry and modern manufacturing, nondegradable low-density polyethylene (LDPE) has been widely used, posing a rising environmental hazard to natural ecosystems and public health. In this study, we isolated a series of LDPE-degrading fungi from landfill sites and carried out LDPE degradation experiments by combining highly efficient degrading fungi in pairs. The results showed that the mixed microorganisms composed of Alternaria sp. CPEF-1 and Trametes sp. PE2F-4 (H-3 group) had a greater degradation effect on heat-treated LDPE (T-LDPE). After 30 days of inoculation with combination strain H-3, the weight loss rate of the T-LDPE film was approximately 154% higher than that of the untreated LDPE (U-LDPE) film, and the weight loss rate reached 0.66 ± 0.06%. Environmental scanning electron microscopy (ESEM) and Fourier transform infrared spectroscopy (FTIR) were used to further investigate the biodegradation impacts of T-LDPE, including the changes on the surface and depolymerization of the LDPE films during the fungal degradation process. Our findings revealed that the combined fungal treatment is more effective at degrading T-LDPE than the single strain treatment, and it is expected that properly altering the composition of the microbial community can help lessen the detrimental impact of plastics on the environment.
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  • 文章类型: Journal Article
    研究水中浓度的微塑料研究很多,但是大多数微塑料沉淀并保留在沉积物中,沉积物中经常报告较高的浓度。因此,MP的积累对生活在沉积物中的底栖鱼类的威胁可能比对中上层鱼类的威胁更大。的存在,通过从两个中上层收集样品,研究了微塑料的丰度和多样性,欧洲凤尾鱼,马鲭鱼和两种底栖鱼类,红乌鱼,在蒂尔基耶的吉雷森省普遍消费的白蚁,位于黑海南部海岸。使用光学显微镜和ATR-FTIR分光光度法对微塑料进行视觉分类和化学成分,连续。采样鱼类的总体发生率和平均微塑料丰度分别为17和1.7±0.18MP鱼-1。MP的大小在0.026-5mm的范围内。在大多数情况下,MP为黑色,占41%。以56%的比率,聚丙烯是主要的聚合物类型。最主要的MP类型被鉴定为纤维,随后是碎片和粒料。鱼中MP含量与富尔顿条件因子之间的关系不足以建立因果关系。
    Microplastic studies investigating concentrations in water are numerous, but the majority of microplastics settle and are retained in sediment, and higher concentrations are regularly reported in sediments. Thus, MPs accumulation may be more threatening to benthic fish living in sediments than to pelagic fish. The presence, abundance and diversity of microplastics were investigated by collecting samples from two pelagic, European anchovy, and horse mackerel and two benthic fish species, red mullet, and whiting that are popularly consumed in Giresun province of Türkiye, located on the southern coast of the Black Sea. Visual classification and chemical compositions of microplastics was performed using a light microscope and ATR-FTIR spectrophotometry, consecutively. The overall incidence and mean microplastics abundance in sampled fishes were 17 and 1.7 ± 0.18 MP fish-1, respectively. MPs were within the range of 0.026-5 mm in size. In most of the cases, the MP was black in color with 41%. With the rates of 56%, polypropylene was the predominant polymer type. The most dominant MP type was identified as fiber followed by fragments and pellets. The relationship between MP amounts in fish and Fulton condition factor was not strong enough to establish a cause-effect relationship.
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  • 文章类型: Journal Article
    角膜擦伤是危重病的常见并发症,插管的病人,可能导致视力障碍。这项研究比较了三种眼部护理方法在该脆弱人群中预防角膜磨损的功效。我们进行了一项随机对照试验,涉及156例ICU插管的成年患者。参与者被随机分配到三个干预组之一(每组52例):(1)仅聚乙烯覆盖,(2)用人工泪滴覆盖聚乙烯,和(3)用Luberatex眼膏覆盖聚乙烯。每位患者随机分配一只眼睛作为对照组,接受标准ICU眼部护理。五天内的每日评估包括标准化的干燥和角膜磨损检查表,眼睛干燥的分级试纸评估,和记录角膜磨损发生率。数据采用描述性和推断性统计学(SPSS-18)进行分析。与人工泪液组(36%,p<0.001)和聚乙烯仅覆盖组(60%,p<0.001)。聚乙烯盖与Luberatex眼膏的联合应用可有效防止插管的ICU患者的角膜磨损。与单独使用或与人工泪液一起使用的聚乙烯覆盖物相比,该方法显示出优异的功效。我们建议将其作为高危人群中预防角膜磨损的标准做法。试用登记。本研究已在伊朗临床试验注册中心(IRCT201506294736N8)注册,可通过www访问。IRCT。Ir.
    Corneal abrasion is a frequent complication in critically ill, intubated patients, potentially leading to visual impairment. This study compares the efficacy of three ocular care methods in preventing corneal abrasion among this vulnerable population. We conducted a randomized controlled trial involving 156 intubated adult patients admitted to the ICU. Participants were randomly allocated to one of three intervention groups (n = 52 per group): (1) polyethylene cover only, (2) polyethylene cover with artificial tear drops, and (3) polyethylene cover with Lubratex eye ointment. One eye per patient was randomly assigned as the control, receiving standard ICU eye care. Daily assessments over five days included a standardized dryness and corneal abrasion checklist, graded strip evaluation of eye dryness, and documentation of corneal abrasion incidence. Data were analyzed using descriptive and inferential statistics (SPSS-18). The incidence of corneal abrasion was significantly lower in the group receiving polyethylene cover with Lubratex eye ointment (4%) compared to the polyethylene cover with artificial tears group (36%, p < 0.001) and the polyethylene cover only group (60%, p < 0.001). The combined application of a polyethylene cover with Lubratex eye ointment effectively prevents corneal abrasion in intubated ICU patients. This method demonstrates superior efficacy compared to polyethylene covers used alone or with artificial tears. We recommend its implementation as standard practice for corneal abrasion prophylaxis in this high-risk population.Trial Registration. This study is registered with the Iranian Registry of Clinical Trials (IRCT201506294736N8) and can be accessed at www.IRCT.ir .
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  • 文章类型: Journal Article
    背景:耳廓重建是整形和重建手术中最具挑战性的手术之一,框架材料的选择对外科医生和患者来说都是一个关键的决定。这项荟萃分析比较了使用肋软骨进行自体耳廓重建与使用多孔聚乙烯植入物进行同种异体重建的结果。
    方法:使用PubMed和Embase数据库进行了文献综述,以检索2000年1月至2024年6月之间发表的文章。分析的结果包括术后并发症,如框架暴露,感染,皮肤坏死,血肿,和肥厚性疤痕,以及患者的满意度。使用R软件中的“metaprop”功能对每项选定研究的重建结果比例进行统计分析。
    结果:14篇文章符合我们的纳入标准。接受聚乙烯植入物重建的组表现出更高的框架暴露率,感染,皮肤坏死,而自体重建组的血肿和肥厚性瘢痕发生率较高。在所有的并发症中,框架暴露是唯一显示两组之间有统计学显著性差异的一个(p<0.0001).在患者满意度方面,那些接受自体软骨重建的人报告了更高的满意度,尽管这一差异在荟萃分析中没有达到统计学意义(p=0.076).
    结论:术后感染等并发症无统计学差异,血肿,皮肤坏死,使用自体肋软骨重建耳廓和使用聚乙烯植入物重建耳廓之间的肥厚性疤痕。然而,使用聚乙烯植入物的重建显示出明显更高的框架暴露率。
    BACKGROUND: Auricle reconstruction is among the most challenging procedures in plastic and reconstructive surgery, and the choice of framework material is a critical decision for both surgeons and patients. This meta-analysis compared the outcomes of autologous auricle reconstruction using costal cartilage with those of alloplastic reconstruction using porous polyethylene implants.
    METHODS: A literature review was conducted using the PubMed and Embase databases to retrieve articles published between January 2000 and June 2024. The outcomes analyzed included postoperative complications such as framework exposure, infection, skin necrosis, hematoma, and hypertrophic scars, as well as patient satisfaction. The proportions of reconstructive outcomes from each selected study were statistically analyzed using the \"metaprop\" function in R software.
    RESULTS: Fourteen articles met our inclusion criteria. The group undergoing polyethylene implant reconstruction exhibited higher rates of framework exposure, infection, and skin necrosis, whereas the autologous reconstruction group experienced higher rates of hematoma and hypertrophic scars. Of all the complications, framework exposure was the only one to show a statistically significant difference between the two groups (p < 0.0001). In terms of patient satisfaction, those who underwent autologous cartilage reconstruction reported a higher rate of satisfaction, although this difference did not reach statistical significance in the meta-analysis (p = 0.076).
    CONCLUSIONS: There is no statistically significant difference in postoperative complications such as infection, hematoma, skin necrosis, and hypertrophic scars between auricle reconstructions using autologous costal cartilage and those using polyethylene implants. However, reconstructions with polyethylene implants show a significantly higher rate of framework exposure.
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  • 文章类型: Journal Article
    限速阶段是气化过程中的炭反应性,这可能受其物理化学结构特征的影响。在这项研究中,原料份额的影响,稻草(RS)和聚乙烯(PE),研究了焦炭的理化性质和气化反应性,并讨论了它们之间的关系。使用热分析仪通过等温实验研究了焦炭的气化反应性。结果表明,添加PE改善了从与PE共热解RS获得的焦炭的比表面积(SSA)和孔体积(Vp)。当PE含量为60wt%时,焦炭的SSA增加了1.31倍,与RSchar相比。共热解炭样品的有序度和气化反应性随着PE含量超过40wt%而增加。共气化早期的炭反应性主要取决于碳质和孔结构的有序度。后期的焦炭反应性受这两个因素的影响,二氧化硅含量会抑制焦炭的共气化反应性。
    The rate limiting stage is char reactivity during gasification that can be influenced by its physicochemical structural characteristics. In this study, the effects of feedstock share, rice straw (RS) and polyethylene (PE), on the physicochemical properties and gasification reactivity of chars were investigated and their relationships were discussed. The char gasification reactivity was investigated via isothermal experiments using a thermal analyzer. The results indicated that the PE addition improved the specific surface area (SSA) and pore volume (Vp) of the char obtained from co-pyrolysis RS with PE. The SSA of the char increased by 1.31 times when the PE content was 60 wt%, compared with that of RS char. The order degree and gasification reactivity of the co-pyrolysis char samples increased with increasing PE content beyond 40 wt%. The char reactivity in the early stage of co-gasification was primarily determined by the order degree of carbonaceous and pore structure. The char reactivity in the later stage was influenced by these two factors and the silicon dioxide content could inhibit the char co-gasification reactivity.
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  • 文章类型: Journal Article
    背景:本研究的目的是使用临床相关的体外肘部磨损测试方法,对非机械连接的全肘关节成形术植入物进行聚乙烯磨损测试,该测试方法模拟了在日常生活范围的轻度至中度活动中使用十年的时间。
    方法:测试方案应用了80°的尺肱骨运动弧,从完全伸展的30°开始,并发展到110°的屈曲。以7°施加力以在肘部上重新产生外翻载荷。采用频率为0.5Hz的可变关节载荷曲线。在牛血清润滑剂中测试植入物5百万次循环(Mc)。表征了植入物组件的失效,并通过重量法测定了聚乙烯的磨损。
    结果:在5Mc之后,小聚乙烯衬套的磨损率为0.56mg/Mc。中等尺寸磨损率为0.28mg/Mc。测试了三个大尺寸,平均磨损率为0.39±0.07mg/Mc。未发现植入物失败。
    结论:该测试重新创建了体内加载环境,并在指定的循环计数下测量了聚乙烯的磨损率。该试验表明比其他关节置换件磨损较小。进一步的临床评估是必要的,以确定这是否转化为减少与磨损相关的全肘关节置换的并发症。
    BACKGROUND: The objective of this study was to perform a polyethylene wear test on a non-mechanically linked total elbow arthroplasty implant using a clinically relevant in-vitro elbow wear test methodology that simulated ten years of use in the light to moderate activity of daily living range.
    METHODS: The test protocol applied an 80° arc of ulnohumeral motion beginning at 30° shy of full extension and progressing to 110° of flexion. Force was applied at 7° to recreate a valgus load on the elbow. A variable joint load profile at a frequency of 0.5 Hz was employed. The implants were tested for 5 million cycles (Mc) in a bovine serum lubricant. Implant component failure was characterized and polyethylene wear was determined gravimetrically.
    RESULTS: After 5 Mc the small polyethylene bushing wear rate was 0.56 mg/Mc. The medium size wear rate was 0.28 mg/Mc. Three large sizes were tested and the average wear rate was 0.39 ± 0.07 mg/Mc. No implant failure was identified.
    CONCLUSIONS: The test recreated an in vivo loading environment and measured polyethylene wear rates at specified cycle counts. The test demonstrated less wear than other joint replacements. Further clinical evaluation is necessary to determine if this translates into reduced complications of total elbow replacement associated with wear.
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  • 文章类型: Journal Article
    平衡被动采样继续越来越多地用于进行原位评估和监测疏水性有机化合物(HOC)。尽管该方法已成功用于包括开放地表水和沉积物在内的多项野外研究中,相对而言,它们在地下水中的使用非常有限。在这项研究中,低密度聚乙烯(LDPE)被动采样器在三个被多环芳烃(PAHs)污染的地下水井中部署了80天。在部署之前,LDPE装载有由氘代PAH组成的性能参考化合物(PRCs),并将其释放用于确定系统平衡。在80天部署期内,对于分子量(MWs)在178至228范围内的PAHs(即蒽,chrysene).测得的自由溶解浓度(Cw)比研究孔中的总过滤浓度(Ctotal)低一到三个数量级。在孔1、2和3处,基于Cw和Ctotal测得的PAHs(ΣPAHs)的总和分别为2.05、0.07和29.2μgL-1和197、59.7和1010μgL-1。一个单独的数据集,包括PAHs的长期(2010年至2022年)总浓度(即,未过滤的)地下水,还提供了基于常规测量的评估地下水井中PAH污染水平的见解。目标分析物的估计原位LDPE每日清除量(2.34至27.56Ld-1)远小于井中遇到的地下水每日周转量(144至348Ld-1),从而消除了对地下水进行消耗采样的可能性。被动采样器。这些结果代表了有关使用LDPE进行平衡被动采样在监测和定量评估地下水中PAHs的实际应用的首次发表研究。此外,这项工作表明,LDPEs是测量地下水中PAHsCw的有用工具,许多生态和人类健康风险评估中的关键污染物。
    Equilibrium passive sampling continues to find increasing use for performing in situ assessments and monitoring of hydrophobic organic compounds (HOCs). Although this method has been successfully used in several field studies including open surface waters and sediments, comparatively, their use in groundwater has been very limited. In this study, low-density polyethylene (LDPE) passive samplers were deployed for 80 days in three groundwater wells contaminated with polycyclic aromatic hydrocarbons (PAHs). Prior to deployment, LDPE was loaded with performance reference compounds (PRCs) consisting of deuterated PAHs and their release used to ascertain system equilibrium. Within the 80-day deployment period, LDPE-groundwater equilibrium was confirmed for PAHs with molecular weights (MWs) in the range of 178 to 228 (i.e. anthracene, chrysene). Measured freely dissolved concentrations (Cw) were between one to three orders of magnitude lower than the total filtered concentrations (Ctotal) in the studied wells. The sum of PAHs (ΣPAHs) measured based on Cw and Ctotal were 2.05, 0.07 and 29.2 μg L-1 and 197, 59.7 and 1010 μg L-1, at wells 1, 2 and 3, respectively. A separate dataset, comprising long-term (2010 to 2022) concentrations of PAHs in total (i.e., unfiltered) groundwater, is also presented to provide insight into PAH contamination levels at the assessed groundwater wells based on conventional measurement. Estimated in situ LDPE daily clearance volumes (2.34 to 27.56 Ld-1) for the target analytes were far less than the daily turnover of ground water (144 to 348 Ld-1) encountered in the wells eliminating the possibility of depletive sampling of the groundwater by the passive samplers. These results represent the first published study on the practical application of equilibrium passive sampling using LDPE for monitoring and quantitatively assessing PAHs in groundwater. Also, this work demonstrates that LDPEs are a useful tool for measuring the Cw of PAHs in groundwater, a critical contaminant in many ecological and human health risk assessments.
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  • 文章类型: Journal Article
    聚乙烯(PE)是世界上使用最广泛的塑料之一。其降解导致产生小颗粒,包括微塑料和纳米塑料(NPs)。塑料颗粒的存在会带来健康风险。这项工作的目的是研究两种模型的无表面活性剂的PENP的毒性,该PENP是由阳离子和阴离子水溶性引发剂聚合乙烯制备的,对人细胞系Caco-2和HT29-MTX。经过物理化学表征,它们的急性和亚急性毒性特征,包括细胞毒性,氧化应激,和遗传毒性,在两种细胞系上进行评估。结果显示培养基中PENP的大小增加。在培养基中吸附血清成分后,接近-10mV的Zeta电位值不再取决于引发剂电荷。然而,阳离子和阴离子PENP的细胞毒性非常不同。时间和浓度依赖性细胞毒性,氧化,仅对于用阳离子引发剂制备的PENP观察到对Caco-2细胞的遗传毒性作用。在HT29-MTX上没有观察到毒性,可能是由于保护性粘液层。从0.1mg的浓度观察到与某些PENP对Caco-2细胞的氧化应激相关的遗传毒性。mL-1后48小时暴露。
    Polyethylene (PE) is one of the most widely used plastics in the world. Its degradation leads to the production of small particles including microplastics and nanoplastics (NPs). Plastic particles\' presence poses a health risk. The aim of this work was to investigate the toxicity of two model surfactant-free PE NPs prepared by polymerization of ethylene from cationic and anionic water-soluble initiators on human cell lines Caco-2 and HT29-MTX. After physicochemical characterization, their acute and subacute toxicity profile, including cytotoxicity, oxidative stress, and genotoxicity, was evaluated on both cell lines. Results showed a size increase of PE NPs in culture medium. Zeta potential values close to -10 mV were no longer dependent on the initiator charge after adsorption of serum components in culture medium. However, the cellular toxicity of the cationic and anionic PE NPs was very different. A time-and-concentration dependent cytotoxic, oxidative, and genotoxic effects on Caco-2 cells were only observed for PE NPs prepared with cationic initiators. No toxicity was observed on HT29-MTX, likely due to the protective mucus layer. Genotoxicity correlated with oxidative stress of some PE NPs on Caco-2 cells was observed from a concentration of 0.1 mg.mL-1 after 48-h exposure.
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