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1.
J Environ Manage ; 260: 110062, 2020 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-31941625

RESUMO

A large number of polyethylene terephthalate (PET) bottles are discarded daily after usage. Thus, plastic bottle recycling has elicited considerable attention in recent years. In this context, this study aims to quantify the environmental and economic impacts of blanket production from 100% recycled waste plastic bottles in China through a life cycle assessment coupled with life cycle costing method. In addition, the environmental impact of replacing coal with natural gas and solar energy was evaluated. Results show that impact categories of global warming and fossil depletion have significant influence on the overall environment. Carbon dioxide, water, iron, coal and chromium (VI) to water are the main contributors to the overall environmental burden. The internal and external costs are $6433/metric ton and $370/metric ton, respectively. Analysis results indicate that the optimization of organic chemicals, recycled polyester filament and steam production processes can reduce environmental and economic burdens substantially. Energy substitutions with natural gas and the use of solar photovoltaic in steam production and electricity generation are effective measures for decreasing environmental impacts. Finally, suggestions based on research results and the current status of waste plastic bottle recycling in China are proposed.


Assuntos
Polietilenotereftalatos , Gerenciamento de Resíduos , China , Reciclagem , Água
2.
Chemosphere ; 239: 124728, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31499314

RESUMO

Numerous of pollutants threaten our planet, for instance plastic wastes causes a huge potential risk on the environment in addition to many of emergened pollutants as pharmaceutical residue in aquatic environments which affecting ecological balance and in-turn affecting human health. Accordingly, this research proposed an innovative facile, one-step synthesis of functionalized magnetic fullerene nanocomposite (FMFN) via catalytic thermal decomposition of sustainable poly (ethylene terephthalate) bottle wastes as feedstock and ferrocene as a catalyst and precursor of magnetite. Growth mechanism of FMFN was discussed and batch experiments were achieved to examine its adsorption efficiency in relation to Ciprofloxacin antibiotic. Different adsorption parameters including time, initial Ciprofloxacin concentration, and solution temperature were investigated and optimized using Response Surface Methodology (RSM) model. In addition, a study on the antibiotic adsorption process impact on the organisms of an ecosystem was conducted using E. coli DH5α, and results validated method's efficiency in overcoming problem of appearance of antibiotic-resistant microbes.


Assuntos
Ciprofloxacino/isolamento & purificação , Fulerenos/química , Nanocompostos/química , Poluentes Químicos da Água/isolamento & purificação , Adsorção , Ciprofloxacino/química , Ecossistema , Escherichia coli , Concentração de Íons de Hidrogênio , Cinética , Fenômenos Magnéticos , Modelos Estatísticos , Plásticos , Polietilenotereftalatos/química , Tomografia por Emissão de Pósitrons , Reciclagem , Temperatura Ambiente , Poluentes Químicos da Água/química , Purificação da Água/métodos , Purificação da Água/estatística & dados numéricos
3.
Chemosphere ; 238: 124560, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31437632

RESUMO

Plastics are the most abundant marine debris globally dispersed in the oceans and its production is rising with documented negative impacts in marine ecosystems. However, the chemical-physical and biological interactions occurring between plastic and planktonic communities of different types of microorganisms are poorly understood. In these respects, it is of paramount importance to understand, on a molecular level on the surface, what happens to plastic fragments when dispersed in the ocean and directly interacting with phytoplankton assemblages. This study presents a computer-aided analysis of electron paramagnetic resonance (EPR) spectra of selected spin probes able to enter the phyoplanktonic cell interface and interact with the plastic surface. Two different marine phytoplankton species were analyzed, such as the diatom Skeletonema marinoi and dinoflagellate Lingulodinium polyedrum, in absence and presence of polyethylene terephthalate (PET) fragments in synthetic seawater (ASPM), in order to in-situ characterize the interactions occurring between the microalgal cells and plastic surfaces. The analysis was performed at increasing incubation times. The cellular growth and adhesion rates of microalgae in batch culture medium and on the plastic fragments were also evaluated. The data agreed with the EPR results, which showed a significant difference in terms of surface properties between the diatom and dinoflagellate species. Low-polar interactions of lipid aggregates with the plastic surface sites were mainly responsible for the cell-plastic adhesion by S. marinoi, which is exponentially growing on the plastic surface over the incubation time.


Assuntos
Diatomáceas/metabolismo , Dinoflagelados/metabolismo , Microalgas/crescimento & desenvolvimento , Fitoplâncton/metabolismo , Plásticos/metabolismo , Polietilenotereftalatos/metabolismo , Ecossistema , Espectroscopia de Ressonância de Spin Eletrônica , Microalgas/metabolismo , Oceanos e Mares , Água do Mar/química , Resíduos/análise
4.
Chemosphere ; 238: 124593, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31446275

RESUMO

This paper presents the abundance, concentration and variability of microplastics (MP) in an urban wastewater treatment plant (WWTP), according to different water parameters and environmental factors, their possible sources and removal efficiency. A total of 352.6 L of wastewater from four stages of the treatment process were processed following a standardized extraction protocol by density separation, trinocular microscopic identification and polymeric analysis by Fourier transform infrared spectroscopy. MP comprised a 46.6% of total microlitter, with a statistically significant removal of 90.3% in the final effluent of the WWTP. Five different shapes were isolated; i.e. fragment, film, bead, fiber, and foam. The most prominent MP forms in the final effluent were fragments and fibers, with the most common size class being 400-600 µm. Seventeen different polymer families were identified, with low-density polyethylene being the most prevalent one (52.4%) in a film form (27.7%), mostly from agriculture greenhouses near the sewage plant and single plastic bags (it is noted that only a year ago consumers are charged for them in Spain). Influent wastewater with high concentrations of suspended solids proved to have a low MP burden with a larger MP size, possibly due to a hetero-aggregation with particulate matter. Agglomeration of polystyrene and polyethylene terephthalate with organic material is also suggested, both with surface energies higher than 25 mN m-1 enough for a high biofouling rate. The sewage plant cushions sharp-point microplastic concentrations during the warm season, allowing a stable performance of the WWTP.


Assuntos
Monitoramento Ambiental/métodos , Esgotos/química , Poluentes Químicos da Água/análise , Purificação da Água , Incrustação Biológica , Polietilenotereftalatos/análise , Poliestirenos/análise , Espanha , Espectroscopia de Infravermelho com Transformada de Fourier
5.
Mar Pollut Bull ; 143: 58-65, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31789166

RESUMO

Microplastics (MPs) in the Arctic Ocean have gained considerable attention due to its ubiquity and impacts within ecosystems. However, little information is available on MPs in the Pacific section of the Arctic Ocean. The present study determined the abundance, distribution, and composition of MPs in surface waters from the Northwestern Pacific, the Bering Sea, and the Chukchi Sea. The MPs abundances varied from 0.018 items/m3 to 0.31 items/m3, with a mean abundance of 0.13 ±â€¯0.11 items/m3. The highest level of MPs was found in the Chukchi Sea. Of all of the detected MPs, polyethylene terephthalate (PET) accounted for the largest proportion of MPs, and fiber was predominant with regard to the total amount. Our results highlighted that the Arctic Ocean is becoming a hotspot for plastic pollution, and the risks posed by MPs need to be paid closer attention in future investigations.


Assuntos
/análise , Poluentes Químicos da Água/análise , Regiões Árticas , Ecossistema , Monitoramento Ambiental , Oceano Pacífico , Polietilenotereftalatos/análise , Poluentes Químicos da Água/química
8.
Environ Sci Pollut Res Int ; 26(36): 36163-36183, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31773528

RESUMO

Bangladesh is 10th among the major plastic waste contributor countries of the globe. Throughout the world, plastic waste disposal is a major concern since it is being nonbiodegradable in nature and hazardous, because of its potential harmful effect on human health and to the environment. Various studies have shown that waste PET (polyethylene terephthalate) plastic bottle filled with sand or other inorganic materials can serve as a useful building material where plastic waste management or recycling process is not very effective and particularly, in low-income communities. Plastic brick use in existing Rohingya refugee camp and newly proposed displacement camp in the coast island-Bhasan Char-as construction material to build new shelters, can be a sustainable use and management of country's plastic waste, and a feasible solution against the shelter issues of Rohingya people. The vulnerability due to heavy wind, monsoon rains, cyclones, and the gaps and lack in funding to build new rigid and safe shelters can be effectively mitigated by using this low-cost, environment-friendly plastic brick as building block in refugee camps.


Assuntos
Materiais de Construção , Polietilenotereftalatos/química , Reciclagem/métodos , Campos de Refugiados , Eliminação de Resíduos/métodos , Bangladesh , Humanos
9.
Environ Monit Assess ; 191(12): 749, 2019 Nov 14.
Artigo em Inglês | MEDLINE | ID: mdl-31728744

RESUMO

Twelve different brands of mineral water were collected from the Algerian market and analyzed to determine the initial antimony (Sb) content in both the PET package and mineral water. Experiments were conducted under different time conditions: 1, 10, to 365 days, different temperatures: 6, 25, and 40 °C, and different bottles sizes: 0.33 L and 1.5 L. The Sb in mineral water bottles varies between 0.50 and 1.12 µg/L for 0.33 L bottles, and 0.37 to 0.77 µg/L for 1.5 L ones. All of these values remain below the limit set by the European Union of 5 µg/L in drinking water. The diffusion coefficient of Sb in PET has been experimentally determined at 6, 25, and 40 °C, after the content of Sb in 1.5 L PET bottles had been determined. In the second part of the study, a factorial design 23 enabled a model the migration of antimony (Sb) in the bottled solutions and highlighted the influencing effects, such as temperature (°C), time (h), and thickness (mm) for two different time domains encompassing the entire validity period of the product. A simple polynomial function based on a single parameter has been determined with a precision indicator R2 = 0.98. This model has the advantage of being simple and fast. The Chronic Daily Intake (CDI) of Sb has been calculated, for adults. It does not exceed the Environmental Protection Agency (USEPA) regulated CDI value of 400 ng/kg/day. The CDI values for children increase as the weight of the children decreases. The passage from the maximum child weight to the minimum value in the study increases the CDI of 77%.


Assuntos
Antimônio/análise , Água Potável/química , Monitoramento Ambiental/métodos , Águas Minerais/análise , Plásticos/química , Polietilenotereftalatos/química , Poluentes Químicos da Água/análise , Adulto , Criança , Humanos , Tomografia por Emissão de Pósitrons , Temperatura Ambiente
10.
Waste Manag ; 100: 296-305, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31568978

RESUMO

Millions of tons of plastic are produced annually, but less than 10% are reported to be recycled. This work sets out to transform environmental plastic (polyethylene terephthalate - PET) waste into aerogels for high-value engineering applications, primarily to enhance the monetary incentive in recycling plastics. Coating techniques, using silicone ceramic (SCC) and (3-aminopropyl)triethoxysilane (APS, or APTES) solutions, are successfully devised to enhance the thermal stability and CO2 adsorption capability of rPET aerogel. The rPET/SCC aerogel exhibits improved thermal stability (up to 600 °C), enhanced thermal insulation (thermal conductivity Kavg = [31.8-34.9] mW/m·K), hydrophobic characteristics (up to 144.7° in contact angle) and enhanced rigidity (Young modulus Eavg = [4.5-124.8] kPa), while maintaining an ultra-low density (ρa = [14-62] g/cm3) and a high porosity (Φavg = [95.6-99.0]%). Moreover, the amine-functionalised rPET aerogel achieves a CO2 adsorption capacity of up to 0.44 mmol CO2/g, superior to several commercial physio-sorbents. These promising results obtained demonstrate that the rPET aerogel is a versatile material suitable for a wide variety of high-value engineering applications, including thermal insulation and direct CO2 capture applications.


Assuntos
Polietilenotereftalatos , Reciclagem , Interações Hidrofóbicas e Hidrofílicas , Porosidade , Condutividade Térmica
11.
Mar Pollut Bull ; 145: 547-554, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31590822

RESUMO

Microplastics are becoming a global concern due to their potential to accumulate pollutants in aquatic environments. In this paper, sulfamethazine (SMT) sorption onto six types of microplastics, including polyamide (PA), polyethylene (PE), polyethylene terephthalate (PET), polypropylene (PP), polystyrene (PS), and polyvinyl chloride (PVC) was investigated by experimental and molecular dynamics simulation methods. The experimental results indicated that SMX sorption reached equilibrium within 16 h. The kinetics of SMT sorption by PA, PVC, PE, and PP could be fitted by pseudo first-order model, while SMT sorption by PA and PET could be described by pseudo second-order model. The partition coefficient Kd values were 38.7, 23.5, 21.0, 22.6, 18.6 and 15.1 L·kg-1 for PA, PE, PS, PET, PVC and PP, respectively. SMT sorption onto microplastics decreased when pH and salinity increased. The molecular dynamics simulation results indicated that the main mechanisms involved in sorption are electrostatic and Van der Waals interaction.


Assuntos
/química , Sulfametazina/química , Poluentes Químicos da Água/química , Adsorção , Concentração de Íons de Hidrogênio , Cinética , Simulação de Dinâmica Molecular , Polietileno/química , Polietilenotereftalatos , Polipropilenos/química , Poliestirenos/química , Cloreto de Polivinila/química , Eletricidade Estática
12.
J Orofac Orthop ; 80(6): 292-303, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31578595

RESUMO

PURPOSE: The mechanical properties of orthodontic aligners made from thermoplastic polymers decrease over time in the intraoral milieu. However, there is a lack of information on this topic in the literature. Thus, the elastic properties of polyethylene terephthalate glycol (PETG) aligner films were investigated in vitro under extreme temperature changes simulated by thermocycling, environmental temperature and water absorption. MATERIALS AND METHODS: A total of 60 specimens made from PETG aligner films (CA Clear Aligner, Scheu Dental, Iserlohn, Germany) were divided into three groups (immersed in distilled water, subjected to accelerated ageing by thermocycling, control). These groups were again divided and tensile testing was performed for all groups at 22 and at 37 °C. Young's modulus (E), 0.2% offset yield strength (Rp02) and ultimate tensile strength (UTS) were evaluated. Water absorption was determined using an analytical scale. RESULTS: All treated specimens showed water absorption, whereby specimens that were thermocycled absorbed 48% more water than the immersed ones. Young's modulus and UTS were significantly lower for all three groups at 37 °C compared to the corresponding groups tested at 22 °C. Thermocycled and immersed groups showed a significantly lower Young's modulus compared to the control group tested at the same temperature. The mean Rp02 was statistically different when comparing the control group tested at 22 °C to the one tested at 37 °C. CONCLUSIONS: The results of this study add to the understanding of the clinically well-known degradation of orthodontic aligners during wear time. Extreme alternating temperatures along with warming up to intraoral temperature and water absorption can reduce the material's Young's modulus and may therefore promote a decrease of resulting orthodontic forces.


Assuntos
Envelhecimento , Água , Módulo de Elasticidade , Alemanha , Teste de Materiais , Polietilenoglicóis , Polietilenotereftalatos , Resistência à Tração
13.
Environ Monit Assess ; 191(11): 666, 2019 Oct 24.
Artigo em Inglês | MEDLINE | ID: mdl-31650329

RESUMO

The presence of several trace elements, heavy metals, and antimony in polyethylene terephthalate-bottled local raw cow milk samples of Igdir region in Turkey was investigated. The milk samples were analyzed by inductively coupled plasma mass spectrometry after microwave-assisted digestion. Milk samples were categorized into three groups according to the element level intensity in the sample. While 70% of samples showed 2.5 times the maximum Turkish and European permissible level of lead, the lowest lead-contaminated sample exhibited 1.25 times this level. All the examined samples exceeded the maximum permissible limit administrated for arsenic and 35% of samples exhibited 5 times this limit. Results showed 40% of samples contain an antimony level higher than the Turkish maximum allowable concentration. The high antimony content of raw milk samples may be related to the release of antimony from the PET (polyethylene terephthalate) bottles. This study showed high contamination levels of the most toxic trace elements, i.e., lead and arsenic in milk and possible antimony contamination from PET bottles which may cause many health hazards for the consumers.


Assuntos
Antimônio/análise , Contaminação de Alimentos/análise , Metais Pesados/análise , Leite/química , Oligoelementos/análise , Animais , Arsênico/análise , Bovinos , Monitoramento Ambiental , Feminino , Inocuidade dos Alimentos , Polietilenotereftalatos , Espectrofotometria Atômica , Turquia
14.
Eklem Hastalik Cerrahisi ; 30(3): 201-11, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31650915

RESUMO

OBJECTIVES: This study aims to evaluate the effects of mesenchymal stem cell (MSC) implantation on vascular graft infections caused by methicillin-resistant Staphylococcus epidermidis (MRSE) and compare with antibiotic treatment. MATERIALS AND METHODS: Healthy adult 56 Wistar rats (age, over 5 months; weighing, 300-350 g) were divided into eight groups. Group 1 was defined as the control group and group 2 was defined as the infected control group. Groups 3 and 4 were defined as Dacron grafted and MRSE infected groups, treated with tigecycline and MSCs, respectively. Groups 5 and 6 were performed polytetrafluoroethylene (PTFE) graft and infected with MRSE. These groups were also administered tigecycline and MSC treatment, respectively. Groups 7 and 8 were infected with MRSE without graft administration and were also performed tigecycline and MSC treatment, respectively. Grafts and soft tissue specimens were collected at 13 days postoperatively. Colony counts of peri-graft tissue were performed. All samples were evaluated by enzyme-linked immunosorbent assay (ELISA) for the markers that determine stem cell activity. RESULTS: The overall success of the treatments was assessed by the number of rats with MRSE recurrence, regardless of graft used. The difference between the untreated group 2, tigecycline groups (3, 5 and 7) and MSCs groups (4, 6 and 8) were statistically significant. Success of MSC and tigecycline treatments was similar in Dacron, PTFE, and non-grafted groups. There was a resistance of MRSE infection in Dacron groups to MSC and tigecycline treatments. This was considered to be indicative of the susceptibility of the Dacron grafts to infection. However, there was no significant difference between group 2 and Dacron groups in terms of bacterial colonization. ELISA results were significant in three cytokines. CONCLUSION: Mesenchymal stem cells can be considered as an alternative treatment option on its own or part of a combination therapy for control of vascular graft infections.


Assuntos
Prótese Vascular/microbiologia , Transplante de Células-Tronco Mesenquimais , Resistência a Meticilina , Infecções Relacionadas à Prótese/terapia , Infecções Estafilocócicas/terapia , Animais , Antibacterianos/farmacologia , Prótese Vascular/efeitos adversos , Células-Tronco Mesenquimais/citologia , Polietilenotereftalatos , Politetrafluoretileno , Infecções Relacionadas à Prótese/microbiologia , Ratos , Ratos Wistar , Staphylococcus epidermidis , Tigeciclina/farmacologia
15.
J Orofac Orthop ; 80(6): 315-326, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31595320

RESUMO

AIM: Derotation of rounded teeth has proved difficult for aligners to achieve. In this study, we investigated the effect of aligner attachment geometry on the three-dimensional (3D) force and moment (F/M) values exerted during derotation of a mandibular canine. MATERIALS AND METHODS: The experiment setup comprised an acrylic mandibular arch model with a separated right canine (tooth 43) mounted on a hexapod via a 3D F/M sensor. Polyethylene terephthalate glycol (PET­G) aligners with thicknesses of 0.5, 0.625, and 0.75 mm were tested in combination with quarter-sphere, vertical-ellipsoid, and pyramidal attachments bonded to tooth 43. The experimentally measured movement consisted of mesio- and distorotation of tooth 43 in 1° steps up to ±15° in each direction. RESULTS: Compared with no attachment, vertical-ellipsoid and quarter-sphere attachments increased the rotational moment by a median factor of 1.5-12.3. Moment increases for pyramidal attachments were significantly smaller (Mann-Whitney U­test, p < 0.05). Quarter-sphere attachments inhibited the intrusive forces up to 6.07° distorotation, whereas the intrusion prevention range for most aligner attachment combinations was significantly smaller (2.95° for vertical-ellipsoid and 2.88° for pyramidal attachments; Mann-Whitney U­test, p < 0.05). None of the attachment geometries could completely prevent intrusive forces during mesiorotation. CONCLUSION: The quarter-sphere geometry had the best overall mechanical properties because it induced relatively high rotational moment increases and counteracted unwanted intrusive forces most effectively of all three geometries. The determined maximum attachment dislodgement and intrusion prevention angles of approximately 6° provide a guide to determining setup increments for mandibular canine derotation.


Assuntos
Desenho de Aparelho Ortodôntico , Técnicas de Movimentação Dentária , Dente Canino , Polietilenoglicóis , Polietilenotereftalatos , Estresse Mecânico
16.
Microb Cell Fact ; 18(1): 171, 2019 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-31601227

RESUMO

BACKGROUND: The biological degradation of plastics is a promising method to counter the increasing pollution of our planet with artificial polymers and to develop eco-friendly recycling strategies. Polyethylene terephthalate (PET) is a thermoplast industrially produced from fossil feedstocks since the 1940s, nowadays prevalently used in bottle packaging and textiles. Although established industrial processes for PET recycling exist, large amounts of PET still end up in the environment-a significant portion thereof in the world's oceans. In 2016, Ideonella sakaiensis, a bacterium possessing the ability to degrade PET and use the degradation products as a sole carbon source for growth, was isolated. I. sakaiensis expresses a key enzyme responsible for the breakdown of PET into monomers: PETase. This hydrolase might possess huge potential for the development of biological PET degradation and recycling processes as well as bioremediation approaches of environmental plastic waste. RESULTS: Using the photosynthetic microalga Phaeodactylum tricornutum as a chassis we generated a microbial cell factory capable of producing and secreting an engineered version of PETase into the surrounding culture medium. Initial degradation experiments using culture supernatant at 30 °C showed that PETase possessed activity against PET and the copolymer polyethylene terephthalate glycol (PETG) with an approximately 80-fold higher turnover of low crystallinity PETG compared to bottle PET. Moreover, we show that diatom produced PETase was active against industrially shredded PET in a saltwater-based environment even at mesophilic temperatures (21 °C). The products resulting from the degradation of the PET substrate were mainly terephthalic acid (TPA) and mono(2-hydroxyethyl) terephthalic acid (MHET) estimated to be formed in the micromolar range under the selected reaction conditions. CONCLUSION: We provide a promising and eco-friendly solution for biological decomposition of PET waste in a saltwater-based environment by using a eukaryotic microalga instead of a bacterium as a model system. Our results show that via synthetic biology the diatom P. tricornutum indeed could be converted into a valuable chassis for biological PET degradation. Overall, this proof of principle study demonstrates the potential of the diatom system for future biotechnological applications in biological PET degradation especially for bioremediation approaches of PET polluted seawater.


Assuntos
Burkholderiales/metabolismo , Hidrolases/metabolismo , Microalgas/metabolismo , Polietilenotereftalatos/metabolismo , Proteínas de Bactérias/metabolismo , Biodegradação Ambiental , Biologia Marinha , Microbiologia da Água
17.
Chemosphere ; 235: 1089-1096, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31561299

RESUMO

WWTPs may be one of the important ways for MPs to enter surface water. In the present study, the influent and effluent from eleven WWTPs in Changzhou were collected and analyzed. At the same time, the abundance, size, color, and shape of MPs in influent and effluent were investigated. The average abundance of MPs in the influent and effluent were 196.00 ±â€¯11.89 n/L and 9.04 ±â€¯1.12 n/L respectively, and the MPs removal efficiency of eleven WWTPs was almost over 90% in which it could be up to 97.15%. MPs were divided into four particle size based on abundance changes, and the size of MPs with the highest abundant was mainly concentrated at 0.1-0.5 mm. Among these MPs, fibers were the main shape in wastewater, followed by fragments, flakes, spheres and films. The colors of MPs in wastewater were various and 14 types of plastics were detected from wastewater using attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR). Moreover, Rayon and PET were the dominant polymer types in eleven WWTPs. The research results provided basic data for the research and supervision of MPs pollution in WWTPs.


Assuntos
Plásticos/análise , Instalações de Eliminação de Resíduos/normas , Águas Residuárias/química , Poluentes Químicos da Água/análise , Celulose/análise , Cor , Tamanho da Partícula , Plásticos/isolamento & purificação , Polietilenotereftalatos/análise , Espectroscopia de Infravermelho com Transformada de Fourier , Eliminação de Resíduos Líquidos
18.
Environ Sci Technol ; 53(20): 12035-12042, 2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31525038

RESUMO

Human exposure to microplastics has been a topic of interest, but measurements of exposure are limited. Pet animals are sentinels of human exposure, as they share a common living environment with humans. In this study, 58 pet (cat and dog) foods and 78 pet feces samples were collected from Albany, NY, USA, for the analysis of polyethylene terephthalate (PET) and polycarbonate (PC) by alkali-assisted thermal depolymerization and liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) methods. PET was detected at concentrations in the range of <1,500 ng/g to 12,000 ng/g (median: <1,500 ng/g) and <1,500 to 4,600 ng/g (median: <1,500 ng/g) in cat and dog foods, respectively. The concentrations of PET in cat (<2,300-340,000 ng/g, median: 61,000 ng/g) and dog (7700-190,000 ng/g, median: 30,000 ng/g) feces were 1-2 orders of magnitude higher than those in pet food samples. A significant positive correlation was found between the concentrations of the monomers (i.e., TPA and BPA) and the corresponding MPs in cat feces. The calculated mean estimated daily intake of PET and PC (calculated from pet food) was lower than that of the mean cumulative daily intake (calculated from pet feces), which suggested that diet is a minor source of exposure to PET and PC in pets.


Assuntos
Plásticos , Polietilenotereftalatos , Animais , Compostos Benzidrílicos , Gatos , Cães , Fezes , Humanos , Cimento de Policarboxilato , Espectrometria de Massas em Tandem , Estados Unidos
19.
BMC Musculoskelet Disord ; 20(1): 396, 2019 Aug 31.
Artigo em Inglês | MEDLINE | ID: mdl-31472679

RESUMO

BACKGROUND: Treatment of anterior cruciate ligament injuries commonly involves the use of polyethylene terephthalate (PET) artificial ligaments for reconstruction. However, the currently available methods require long fixation periods, thereby necessitating the development of alternative methods to accelerate the healing process between tendons and bones. Thus, we developed and evaluated a novel technique that utilizes silicate-substituted strontium (SrSiP). METHODS: PET films, nano-coated with SrSiP, were prepared. Bone marrow mesenchymal cells (BMSCs) from femurs of male rats were cultured and seeded at a density of 1.0 × 104/cm2 onto the SrSiP-coated and non-coated PET film, and subsequently placed in an osteogenic medium. The osteocalcin concentration secreted into the medium was compared in each case. Next, PET artificial ligament, nano-coated with SrSiP, were prepared. BMSCs were seeded at a density of 4.5 × 105/cm2 onto the SrSiP-coated, and non-coated artificial ligament, and then placed in osteogenic medium. The osteocalcin and calcium concentrations in the culture medium were measured on the 8th, 10th, 12th, and 14th day of culture. Furthermore, mRNA expression of osteocalcin, alkaline phosphatase (ALP), bone morphogenetic protein-2 (BMP2), and runt-related transcription factor 2 (Runx2) was evaluated by qPCR. We transplanted the SrSiP-coated and non-coated artificial ligament to the tibiae of mature New Zealand white rabbits. Two months later, we sacrificed them and histologically evaluated them. RESULTS: The secretory osteocalcin concentration in the medium on the film was significantly higher for the SrSiP group than for the non-coated group. Secretory osteocalcin concentration in the medium on the artificial ligament was also significantly higher in the SrSiP group than in the non-coated group on the 14th day. Calcium concentration on the artificial ligament was significantly lower in the SrSiP group than in the non-coated group on the 8th, 10th, 12th, and 14th day. In qPCR as well, OC, ALP, BMP2, and Runx2 mRNA expression were significantly higher in the SrSiP group than in the non-coated group. Newly formed bone was histologically found around the artificial ligament in the SrSiP group. CONCLUSIONS: Our findings demonstrate that artificial ligaments using SrSiP display high osteogenic potential and thus may be efficiently used in future clinical applications.


Assuntos
Lesões do Ligamento Cruzado Anterior/terapia , Interface Osso-Implante , Materiais Revestidos Biocompatíveis/farmacologia , Nanoestruturas/química , Polietilenotereftalatos/farmacologia , Animais , Apatitas/química , Apatitas/farmacologia , Cálcio/metabolismo , Diferenciação Celular , Células Cultivadas , Materiais Revestidos Biocompatíveis/química , Materiais Revestidos Biocompatíveis/uso terapêutico , Meios de Cultura/análise , Modelos Animais de Doenças , Humanos , Masculino , Teste de Materiais , Células-Tronco Mesenquimais , Osseointegração/efeitos dos fármacos , Osteocalcina/análise , Osteocalcina/metabolismo , Osteogênese/efeitos dos fármacos , Polietilenotereftalatos/química , Polietilenotereftalatos/uso terapêutico , Cultura Primária de Células , Coelhos , Ratos , Silicatos/farmacologia , Estrôncio/química , Estrôncio/farmacologia , Fatores de Tempo , Cicatrização/efeitos dos fármacos
20.
Anal Chim Acta ; 1082: 186-193, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31472708

RESUMO

Exosomes are one class of extracellular vesicles (30-150 nm diameter) that are secreted by cells. These small vesicles hold a great deal of promise in disease diagnostics, as they display the same protein biomarkers as their originating cell. On a cellular level, exosomes are attributed to playing a key role in intercellular communication, and may eventually be exploited for targeted drug delivery. In order for exosomes to become useful in disease diagnostics, and as burgeoning drug delivery platforms, they must be isolated efficiently and effectively without compromising their structure. Plasma from peripheral blood is an excellent source of exosomes, as it is easily collected and the process does not normally cause undue discomfort to the patient. Unfortunately, blood plasma content is complex, containing abundant amounts of soluble proteins and aggregates, making exosomes extremely difficult to isolate in high purity from plasma. Most current exosome isolation methods have practical challenges including being too time-consuming and labor intensive, destructive to the exosomes, or too costly for use in clinical settings. To this end, this study examines the use of poly(ethylene terephthalate) (PET) capillary-channeled polymer (C-CP) fibers in a hydrophobic interaction chromatography (HIC) protocol to isolate exosomes from a human plasma sample. Initial results demonstrate the ability to isolate exosomes with comparable yields and size distributions and on a much faster time scale when compared to traditional isolation methods, while also alleviating concomitant proteins and other impurities. As a demonstration of the potential quantitative utility of the approach, a linear response (particles injected on-column vs peak area) using a commercial exosome standard was established using a standard UV absorbance detector. Based on the calibration function, the concentration of the original human plasma sample was determined and subsequently confirmed by NTA measurement. The potential for scalable separations covering sub-milliliter spin-down solid phase extraction tips to the preparative scale is anticipated.


Assuntos
Células Sanguíneas , Exossomos , Cromatografia/instrumentação , Cromatografia/métodos , Humanos , Interações Hidrofóbicas e Hidrofílicas , Polietilenotereftalatos/química
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